105mm in old frame

Discuss light weight issues concerning mountain bikes & parts.

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d4_d00d

by d4_d00d

would any of you know whether an 105mm travel fork (marzocchi mx) would fit into a 1998 giant terrago frame?

im talking about geometry, wheelbase, angles, 1"1/8, and stuff like that

i know that i will have to buy a aheadset, so this is not the question

greets to you and thanks in advance
d4_d00d

by Weenie


JK
Posts: 1057
Joined: Tue Oct 22, 2002 7:49 pm
Location: The Netherlands - Europe

by JK

No, it does not fit. No question about it.

The geometry of most frames of that age are corrected for forks of around 60mm of travel , if at all suspension corrected! Your Terrago was a relativy cheap priced bike at the time, so chances are that it is designed to take no suspension what so ever.

If you would put in a 105mm fork, you would seriously upset your geometry, meaning you would have a tremendously slack head angle and an very lenghty wheelbase. This would create a very slow-steering bike.

JK

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Florian
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by Florian

JK wrote:No, it does not fit. No question about it.


That's also my opinion.

Although I'd say that the geometries of most frames in 1998 were already designed for about 80 mm travel.

If you want a light fork, I'd recommend you to look out for a RockShox Indy SL (60 mm) or Indy SL LT (75 mm) on eBay.

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Cyco
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Joined: Sat Nov 30, 2002 4:49 am

by Cyco

I agree with JK and the admin, the fork will be to long. The recomendation I give to customers is that a 20mm travel increase is the max. you can expect a bike to cope with. This is for XC use. If you ride more aggressivly your frame is probably already struggeling to cope and the longer fork could cause it to break.

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bladteth
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Joined: Wed Jun 04, 2003 2:24 am
Location: Sydney, Australia

by bladteth

d4_d00d,

Giant Terrago '98 has head tube angle of 72 degrees (measured) with rigid fork 388 mm long (drop out to crown). Marzocchi MX is 478 mm long, 90 mm longer than my rigid fork. For every 17.5 mm increase in length, there is approximately 1 degree change in head tube angle. If you fit Marzocchi into Terrago head tube, the angle will be about 67 degrees, which is rather slack (chopper style) and you will have to steer your bike more with your body than handlebars. It's hard to explain, but to me it just feels weird. I've ridden my Terrago '98 with RST Mozo Pro '99 (89 claimed travel, 461 mm long) with no problems, but I can't recommend longer fork for this frame.
Best regards,
Rado bladteth Rzeznicki

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