specs for a 1990 Bridgestone MB-5 fork?

[Kevin Gammon]

I've finally replaced my MB5 with a Trek Fuel 98, and I'm going to
rebuild my MB5 into a street/cross bike. I made the mistake of putting
front suspension on the MB5 (which did give my arms a relief, but
totally screwed up the steering/handling). I made the double mistake
of losing the original fork. Does anybody know the exact specs of that
fork-- 1" 1-1/8"? Rake? Size? (140mmx50mm? 170mmx50mm?) My frame is a
46cm (which is about 18" from center of bb to top of seat tube). I'm
pretty sure the fork was a Tange CrMo, but I'd love to put on a
something lighter like a Ritchey Logic-- as long as the specs are
identical. The handling with the original fork was incredible. I'd
love any other suggestions on components. I plan on using it for some
road riding, possibly a road triathlon (I've only done mtb triathlons,
but I may do some on-road later), and perhaps as a cross bike. It
currently has XT (1991) front/rear derailleur, cranks, rear hub (on
mavic wheel). The front wheel is stock. Tires are huge WTB 2.4.x26.
Brakes are Avid SD5 V-brakes. It also has top-mount XT-thumbshifters.
Any info would be much appreciated!

[Reco Diver]

(Kevin Gammon) wrote in message >...
> I've finally replaced my MB5 with a Trek Fuel 98, and I'm going to
> rebuild my MB5 into a street/cross bike. I made the mistake of putting
> front suspension on the MB5 (which did give my arms a relief, but
> totally screwed up the steering/handling). I made the double mistake
> of losing the original fork. Does anybody know the exact specs of that
> fork-- 1" 1-1/8"? Rake? Size? (140mmx50mm? 170mmx50mm?) My frame is a
> 46cm (which is about 18" from center of bb to top of seat tube). I'm
> pretty sure the fork was a Tange CrMo, but I'd love to put on a
> something lighter like a Ritchey Logic-- as long as the specs are
> identical.

The length of steerer depends on the length of the MB-5 headtube.
Measure it up. Ritchey (in 1991) gave out these numbers a guide lines:

Steerer length Head tube
127mm 75-90mm
140mm 85-100mm
165mm 100-130mm
190mm 135-155mm
215mm 155-180mm

The offset for a logic fork was 1.8 inches ~46mm. The offset for a
Koski fork, which came on the 1990 an 1991 MB-1's was 48mm. They were
both one inch steerers.

One thing to consider is the length from the dropout to the bottom of
the crownrace. Rigid forks for "suspension corrected frames" were
produced, and are longer than the earlier rigid forks. I can measure
up a Koski later this afternoon, but IIRC the measurement is ~400mm
for a non suspension corrected rigid fork.

R