#11
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Trek BB90
On 8/8/2020 6:07 PM, jbeattie wrote:
On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote: When I got my Trek Madone if became rapidly clear why it was so cheap. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing. With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world. So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them. So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened. You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB. -- Jay Beattie. Yup. I changed the BB90 bearings on my Domane without fixing the "click." Turns out it was the "IsoSpeed" bearing at the seat cluster. (Google Domane IsoSpeed if the idea of a bearing in the seat cluster sounds bizarre.) It had rusted (too many rain rides, I guess). Replaced that and noise went away. I think some Madones now have the IsoSpeed seat cluster; worth a check. Mark J. |
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#12
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Trek BB90
On Sunday, August 9, 2020 at 2:29:42 PM UTC-7, Mark J. wrote:
On 8/8/2020 6:07 PM, jbeattie wrote: On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote: When I got my Trek Madone if became rapidly clear why it was so cheap. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing. With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world. So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them. So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened. You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB. -- Jay Beattie. Yup. I changed the BB90 bearings on my Domane without fixing the "click." Turns out it was the "IsoSpeed" bearing at the seat cluster. (Google Domane IsoSpeed if the idea of a bearing in the seat cluster sounds bizarre.) It had rusted (too many rain rides, I guess). Replaced that and noise went away. I think some Madones now have the IsoSpeed seat cluster; worth a check. Mark J. Mine is a 2012 before Trek decided that they were more clever than Lance Armstrong. |
#13
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Trek BB90
On 8/9/2020 11:47 AM, Tom Kunich wrote:
On Saturday, August 8, 2020 at 6:08:01 PM UTC-7, jbeattie wrote: On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote: When I got my Trek Madone if became rapidly clear why it was so cheap. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing. With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world. So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them. So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened. You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB. -- Jay Beattie. Being on the drive side it cannot be crank torque, the pedals are new so the bearings are extremely unlikely to be loose and usually make noise at the ends of the crank revolutions both top and bottom. Cyclical clicks in exactly the same location almost always means that you have a loose bottom bracket bearing. But of course before I disassemble anything I check everything out. That is what a bike repair stand is for. Before doing anything else, find an able willing assistant (who is not our age with hearing impairment). Get on your bike with your shoes and hold the front brake firmly tight. Lean on something (doorway, chair back) with you other hand. Press as hard as you are able on the right crank (around 3:00 position). Backpedal and repeat for the left crank. Hard. Continue in that cycle as assistant listens near the BB area, at the rear wheel and so on. I find a finger on a chainring bolt or RH cup/bearing or pedal spindle to sometimes be edifying (you can talk with assistant as you do this so there are no mangled fingers). A mechanic's stethoscope is also useful. We replace some crank bearings at rider request which sometimes are a misdiagnosis of a pedal/skewer/spoke/chainring bolt/saddle noise. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#14
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Trek BB90
On Sun, 9 Aug 2020 18:20:55 +0000 (UTC), Ralph Barone
wrote: I think that the issue with shimming is that the required shim thickness (half the difference in diameters) is likely to be in the “tinfoil or less” range, which then results in excessive grief trying not to shred it on insertion. That is where Loctite excels. Most of the shim sources I listed show 0.001 inch shims. For reference, household aluminum foil is between 0.0004 and 0.0007 inches thick. I think you'll find that brass and steel shims are quite a bit stronger than aluminum foil. Shredding the shim on insertion is certainly a risk. I had use shims to fix an industrial machine where the hole had been beaten into an oval shape by shaft vibration. I bored and honed out the hole, but couldn't find a bearing with an exact fit. So, I shimmed it. It took me about 6 tries to insert the bearing without ruining the shim. What finally worked was to pre-roll the (brass) shim into a circle, leaving a small gap at the ends. I intentionally made the shim wider than the bearing. I tacked the shim into the machine with a few tiny dots of cyanoacrylate adhesive. Keep the glue dots small as they are expected to crack as the bearing is inserted. I put some grease on the outside of the bearing, but I suspect that wasn't necessary. Using an arbor press, I started pushing the bearing into the machine and stopped after about 3 mm. With the bearing firmly holding the shim in place, I bent the excess shim material outward so that further pressing of the bearing would not push the shim into the machine. I then completed installing the bearing with the arbor press. When done, I scored the exposed part of the shim with an Exacto knife, and peeled away the excess. Methinks the same procedure will work with a bottom bracket bearing. However, we're all making the assumption that the replacement bearing is correctly sized. Interference fit bearing come in various OD sizes. It should be possible to find a replacement bearing with the correct (interference) fit. https://www.google.com/search?tbm=isch&q=bearing+fit+table However, before ordering, I would pull the current bearing, remove the Loctite, and measure the inside diameter of the bottom bracket with a bore hole micrometer. If it's an oval, make it round before proceding. Hmmm... maybe it is the wrong bearing? Tripeak replacement comes in standard and "snug-fit". http://cycletaiwan.com/tripeak-bb90-bb95-standard-snug-fit-bearing-kit-trek-only.html Maybe a snug-fit bearing will solve the problem without a shim? Trek BB90 Problems Solved: https://www.bbinfinite.com/blogs/news/trek-bb90-problems-solved-1 -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#15
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Trek BB90
On Sun, 09 Aug 2020 18:48:27 -0700, Jeff Liebermann
wrote: On Sun, 9 Aug 2020 18:20:55 +0000 (UTC), Ralph Barone wrote: I think that the issue with shimming is that the required shim thickness (half the difference in diameters) is likely to be in the “tinfoil or less” range, which then results in excessive grief trying not to shred it on insertion. That is where Loctite excels. Most of the shim sources I listed show 0.001 inch shims. For reference, household aluminum foil is between 0.0004 and 0.0007 inches thick. I think you'll find that brass and steel shims are quite a bit stronger than aluminum foil. Shredding the shim on insertion is certainly a risk. I had use shims to fix an industrial machine where the hole had been beaten into an oval shape by shaft vibration. I bored and honed out the hole, but couldn't find a bearing with an exact fit. So, I shimmed it. It took me about 6 tries to insert the bearing without ruining the shim. What finally worked was to pre-roll the (brass) shim into a circle, leaving a small gap at the ends. I intentionally made the shim wider than the bearing. I tacked the shim into the machine with a few tiny dots of cyanoacrylate adhesive. Keep the glue dots small as they are expected to crack as the bearing is inserted. I put some grease on the outside of the bearing, but I suspect that wasn't necessary. Using an arbor press, I started pushing the bearing into the machine and stopped after about 3 mm. With the bearing firmly holding the shim in place, I bent the excess shim material outward so that further pressing of the bearing would not push the shim into the machine. I then completed installing the bearing with the arbor press. When done, I scored the exposed part of the shim with an Exacto knife, and peeled away the excess. Methinks the same procedure will work with a bottom bracket bearing. :-) The classic method to repair out of round holes is (FIRST) obtain a bearing with an O.D. larger then the current and then bore the hole to fit the new bearing :-) However, we're all making the assumption that the replacement bearing is correctly sized. Interference fit bearing come in various OD sizes. It should be possible to find a replacement bearing with the correct (interference) fit. https://www.google.com/search?tbm=isch&q=bearing+fit+table However, before ordering, I would pull the current bearing, remove the Loctite, and measure the inside diameter of the bottom bracket with a bore hole micrometer. If it's an oval, make it round before proceding. Hmmm... maybe it is the wrong bearing? Tripeak replacement comes in standard and "snug-fit". http://cycletaiwan.com/tripeak-bb90-bb95-standard-snug-fit-bearing-kit-trek-only.html Maybe a snug-fit bearing will solve the problem without a shim? Trek BB90 Problems Solved: https://www.bbinfinite.com/blogs/news/trek-bb90-problems-solved-1 -- Cheers, John B. |
#16
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Trek BB90
On Sunday, August 9, 2020 at 9:36:50 PM UTC-7, John B. wrote:
On Sun, 09 Aug 2020 18:48:27 -0700, Jeff Liebermann wrote: On Sun, 9 Aug 2020 18:20:55 +0000 (UTC), Ralph Barone wrote: I think that the issue with shimming is that the required shim thickness (half the difference in diameters) is likely to be in the “tinfoil or less” range, which then results in excessive grief trying not to shred it on insertion. That is where Loctite excels. Most of the shim sources I listed show 0.001 inch shims. For reference, household aluminum foil is between 0.0004 and 0.0007 inches thick. I think you'll find that brass and steel shims are quite a bit stronger than aluminum foil. Shredding the shim on insertion is certainly a risk. I had use shims to fix an industrial machine where the hole had been beaten into an oval shape by shaft vibration. I bored and honed out the hole, but couldn't find a bearing with an exact fit. So, I shimmed it. It took me about 6 tries to insert the bearing without ruining the shim. What finally worked was to pre-roll the (brass) shim into a circle, leaving a small gap at the ends. I intentionally made the shim wider than the bearing. I tacked the shim into the machine with a few tiny dots of cyanoacrylate adhesive. Keep the glue dots small as they are expected to crack as the bearing is inserted. I put some grease on the outside of the bearing, but I suspect that wasn't necessary. Using an arbor press, I started pushing the bearing into the machine and stopped after about 3 mm. With the bearing firmly holding the shim in place, I bent the excess shim material outward so that further pressing of the bearing would not push the shim into the machine. I then completed installing the bearing with the arbor press. When done, I scored the exposed part of the shim with an Exacto knife, and peeled away the excess. Methinks the same procedure will work with a bottom bracket bearing. :-) The classic method to repair out of round holes is (FIRST) obtain a bearing with an O.D. larger then the current and then bore the hole to fit the new bearing :-) However, we're all making the assumption that the replacement bearing is correctly sized. Interference fit bearing come in various OD sizes. It should be possible to find a replacement bearing with the correct (interference) fit. https://www.google.com/search?tbm=isch&q=bearing+fit+table However, before ordering, I would pull the current bearing, remove the Loctite, and measure the inside diameter of the bottom bracket with a bore hole micrometer. If it's an oval, make it round before proceding. Hmmm... maybe it is the wrong bearing? Tripeak replacement comes in standard and "snug-fit". http://cycletaiwan.com/tripeak-bb90-bb95-standard-snug-fit-bearing-kit-trek-only.html Maybe a snug-fit bearing will solve the problem without a shim? Trek BB90 Problems Solved: https://www.bbinfinite.com/blogs/news/trek-bb90-problems-solved-1 -- Cheers, John B. Ruckus, our local carbon repair shop, has a number of methods for fixing carbon BBs. I think they would just build up the shell and ream to dimension with something like Tom's bike. On standard BB30 shells, they can also bond-in a piece of tube made by Enve and just turn the bike into PF30. https://ruckuscomp.com/news/2015/10/09/30-is-the-new-30 Tom can also buy the OS bearings made for sloppy Trek frames. -- Jay Beattie. |
#17
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Trek BB90
On Sunday, August 9, 2020 at 5:15:01 PM UTC-7, AMuzi wrote:
On 8/9/2020 11:47 AM, Tom Kunich wrote: On Saturday, August 8, 2020 at 6:08:01 PM UTC-7, jbeattie wrote: On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote: When I got my Trek Madone if became rapidly clear why it was so cheap.. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing. With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world. So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them. So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened. You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB. -- Jay Beattie. Being on the drive side it cannot be crank torque, the pedals are new so the bearings are extremely unlikely to be loose and usually make noise at the ends of the crank revolutions both top and bottom. Cyclical clicks in exactly the same location almost always means that you have a loose bottom bracket bearing. But of course before I disassemble anything I check everything out. That is what a bike repair stand is for. Before doing anything else, find an able willing assistant (who is not our age with hearing impairment). Get on your bike with your shoes and hold the front brake firmly tight. Lean on something (doorway, chair back) with you other hand. Press as hard as you are able on the right crank (around 3:00 position). Backpedal and repeat for the left crank. Hard. Continue in that cycle as assistant listens near the BB area, at the rear wheel and so on. I find a finger on a chainring bolt or RH cup/bearing or pedal spindle to sometimes be edifying (you can talk with assistant as you do this so there are no mangled fingers). A mechanic's stethoscope is also useful. We replace some crank bearings at rider request which sometimes are a misdiagnosis of a pedal/skewer/spoke/chainring bolt/saddle noise. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I hadn't thought of a lose crank bolt which could offer the same sort of noise in the same sort of position. |
#18
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Trek BB90
On Monday, August 10, 2020 at 7:38:03 AM UTC-7, jbeattie wrote:
On Sunday, August 9, 2020 at 9:36:50 PM UTC-7, John B. wrote: On Sun, 09 Aug 2020 18:48:27 -0700, Jeff Liebermann wrote: On Sun, 9 Aug 2020 18:20:55 +0000 (UTC), Ralph Barone wrote: I think that the issue with shimming is that the required shim thickness (half the difference in diameters) is likely to be in the “tinfoil or less” range, which then results in excessive grief trying not to shred it on insertion. That is where Loctite excels. Most of the shim sources I listed show 0.001 inch shims. For reference, household aluminum foil is between 0.0004 and 0.0007 inches thick. I think you'll find that brass and steel shims are quite a bit stronger than aluminum foil. Shredding the shim on insertion is certainly a risk. I had use shims to fix an industrial machine where the hole had been beaten into an oval shape by shaft vibration. I bored and honed out the hole, but couldn't find a bearing with an exact fit. So, I shimmed it. It took me about 6 tries to insert the bearing without ruining the shim. What finally worked was to pre-roll the (brass) shim into a circle, leaving a small gap at the ends. I intentionally made the shim wider than the bearing. I tacked the shim into the machine with a few tiny dots of cyanoacrylate adhesive. Keep the glue dots small as they are expected to crack as the bearing is inserted. I put some grease on the outside of the bearing, but I suspect that wasn't necessary. Using an arbor press, I started pushing the bearing into the machine and stopped after about 3 mm. With the bearing firmly holding the shim in place, I bent the excess shim material outward so that further pressing of the bearing would not push the shim into the machine. I then completed installing the bearing with the arbor press. When done, I scored the exposed part of the shim with an Exacto knife, and peeled away the excess. Methinks the same procedure will work with a bottom bracket bearing. :-) The classic method to repair out of round holes is (FIRST) obtain a bearing with an O.D. larger then the current and then bore the hole to fit the new bearing :-) However, we're all making the assumption that the replacement bearing is correctly sized. Interference fit bearing come in various OD sizes. It should be possible to find a replacement bearing with the correct (interference) fit. https://www.google.com/search?tbm=isch&q=bearing+fit+table However, before ordering, I would pull the current bearing, remove the Loctite, and measure the inside diameter of the bottom bracket with a bore hole micrometer. If it's an oval, make it round before proceding. Hmmm... maybe it is the wrong bearing? Tripeak replacement comes in standard and "snug-fit". http://cycletaiwan.com/tripeak-bb90-bb95-standard-snug-fit-bearing-kit-trek-only.html Maybe a snug-fit bearing will solve the problem without a shim? Trek BB90 Problems Solved: https://www.bbinfinite.com/blogs/news/trek-bb90-problems-solved-1 -- Cheers, John B. Ruckus, our local carbon repair shop, has a number of methods for fixing carbon BBs. I think they would just build up the shell and ream to dimension with something like Tom's bike. On standard BB30 shells, they can also bond-in a piece of tube made by Enve and just turn the bike into PF30. https://ruckuscomp.com/news/2015/10/09/30-is-the-new-30 Tom can also buy the OS bearings made for sloppy Trek frames. -- Jay Beattie. If I cannot get it to work with correct size bearings I would take it to the Trek factory store in Livermore so that any serious damage would be on their hands. I could use a new Madone if they ruin the old one. |
#19
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Trek BB90
On 8/9/2020 8:14 PM, AMuzi wrote:
On 8/9/2020 11:47 AM, Tom Kunich wrote: On Saturday, August 8, 2020 at 6:08:01 PM UTC-7, jbeattie wrote: On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote: When I got my Trek Madone if became rapidly clear why it was so cheap. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing. With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world. So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them. So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened. You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB. -- Jay Beattie. Being on the drive side it cannot be crank torque, the pedals are new so the bearings are extremely unlikely to be loose and usually make noise at the ends of the crank revolutions both top and bottom. Cyclical clicks in exactly the same location almost always means that you have a loose bottom bracket bearing. But of course before I disassemble anything I check everything out. That is what a bike repair stand is for. Before doing anything else, find an able willing assistant (who is not our age with hearing impairment). Get on your bike with your shoes and hold the front brake firmly tight. Lean on something (doorway, chair back) with you other hand. Press as hard as you are able on the right crank (around 3:00 position). Backpedal and repeat for the left crank. Hard. Continue in that cycle as assistant listens near the BB area, at the rear wheel and so on.Â* I find a finger on a chainring bolt or RH cup/bearing or pedal spindle to sometimes be edifying (you can talk with assistant as you do this so there are no mangled fingers). A mechanic's stethoscope is also useful. We replace some crank bearings at rider request which sometimes are a misdiagnosis of a pedal/skewer/spoke/chainring bolt/saddle noise. I strongly agree with Andrew's method. I've used it myself (although not with an assistant). If an assistant is helping and a mechanic's stethoscope isn't available, a workable substitute can be a dowel, yardstick etc. Hold one end touched to the suspected part and the other end held against one's ear. Before buying the stethoscope, I used that trick on car engines. -- - Frank Krygowski |
#20
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Trek BB90
On 8/10/2020 11:37 AM, Tom Kunich wrote:
On Sunday, August 9, 2020 at 5:15:01 PM UTC-7, AMuzi wrote: On 8/9/2020 11:47 AM, Tom Kunich wrote: On Saturday, August 8, 2020 at 6:08:01 PM UTC-7, jbeattie wrote: On Saturday, August 8, 2020 at 3:15:40 PM UTC-7, Tom Kunich wrote: When I got my Trek Madone if became rapidly clear why it was so cheap. The bearings in the BB90 were rather loose. Now there are several methods of fixing this - one is to use a strong locktite-type compound which locked the bearings in place and one is the Trek way which is to put an oversize bearing in place of the stock bearing. With normal caution as an Engineer I chose the least damaging method first. I followed the directions on the locktite and glued the "just fits" bearing into place and allowed it to dry the requisite 48 hours.. Well, climbing one of the local hills last Tuesday the BB90 began to "click" in the same place every revolution on the drive side pedal. This means the glued drive side bearing has come loose. Inasmuch as I am presently working on the Colnago I won't look at this until later. Another choice has come up - that is to check the bearing that is presently in the Madone, to see if it is undersize. That might be the case since the bearings more easily obtained from Trek are Chinese and let's say they aren't the finest quality bearing available. Hambini of one piece BB push in bearing fame who hates BB90 also can supply NTN bearings which are exactly the right size. NTN is a Japanese bearing manufacturer that supplies the best bearings in the world. So when I remove the bearing that is presently flopping around in there I can closely measure it if I can remember where I put my micrometers. Failing that I do have a digital caliper that is fairly accurate to two decimal places. If the bearing that is in there is undersized by any significant amount (which is common with Chinese bearings.) I will get the bearing set from Hambini and install those before going to the extreme of those oversize Trek bearings which are so oversize that they can distort the bearing cups. This screws up the bearing and generally causes premature failure though "premature" is sort of an undefined term that might mean it only lasts for 1,000 hours. Chinese bearings would probably only last for twice that anyway. NTN bearings virtually last forever under the sorts of loadings that the BB90 puts on them. So presently I'm riding the Emonda and trying to go no lower than the 28 tooth so that I can get a little more training in my legs. I am presently at 80,000 feet of climbing when I would normally be at double that. I normally close a year off with over 200,000 feet of climbing. Judging from the way that my legs felt today after a couple of 900 foot climbs I don't think that I will make 125,000 but stranger things have happened. You should also check the crank bolt torque and maybe swap the pedals out, check the chain ring bolts and even the rear QR before pressing in new bearings. Cyclical clicks can come from places other than the BB. -- Jay Beattie. Being on the drive side it cannot be crank torque, the pedals are new so the bearings are extremely unlikely to be loose and usually make noise at the ends of the crank revolutions both top and bottom. Cyclical clicks in exactly the same location almost always means that you have a loose bottom bracket bearing. But of course before I disassemble anything I check everything out. That is what a bike repair stand is for. Before doing anything else, find an able willing assistant (who is not our age with hearing impairment). Get on your bike with your shoes and hold the front brake firmly tight. Lean on something (doorway, chair back) with you other hand. Press as hard as you are able on the right crank (around 3:00 position). Backpedal and repeat for the left crank. Hard. Continue in that cycle as assistant listens near the BB area, at the rear wheel and so on. I find a finger on a chainring bolt or RH cup/bearing or pedal spindle to sometimes be edifying (you can talk with assistant as you do this so there are no mangled fingers). A mechanic's stethoscope is also useful. We replace some crank bearings at rider request which sometimes are a misdiagnosis of a pedal/skewer/spoke/chainring bolt/saddle noise. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I hadn't thought of a lose crank bolt which could offer the same sort of noise in the same sort of position. Years ago, in the middle of nowhere (well, western Ohio) on a solo tour, I had one of those loose crank bolt events. It was a great feeling to go from impending doom to silence and joy using only an allen wrench. -- - Frank Krygowski |
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