Mountain Biking - Fork Travel

Apart from the obvious of more suspension, is there any other big changes that can happen from switching fm a 100mm travel to 80mm, i.e lower BB, lower bar height.. e.t.c
Also would an 80mm fork be less forgiving on the trail ?

The reason I ask is I have a pretty light race fork on my HT and on the FS which I race I have a 100mm fork, it would make sense to switch the lighter fork to the racing bike, it also seems to be standard that 80mm travel is used for xc racing.

I am just wondering what kind of effect it would have to the feel & handling - some of the courses are very technical & I am sometimes at the limit of my still improving abilities... will I really notice switching to 20mm shorter travel.


Thanks for any advice....

So many variables. If the stack height is equal and you reduce travel there will be no change. If the relative stack height is the same then the bb will drop a tiny amount and the HA will steepen. As for less forgiving, this depends on the type of trails and the quality of fork.

I don't like a steep HA, on the steeps it is not as aggresive or quick handling which I prefer.

thanks... you lost me a bit..

what is the stack height ? height of the top of the fork (excl tube) when not travelled.
what is difference between stack height and relative stack height ?

What is HA ?

Both forks are rock shox, REBA and SID.

Sorry not stack...my brain wasn't turned on yet, I meant axle to crown height. Relative meaning if the forks have the same stack height. If they do then the travel would make a diff. If they have different stack heights (take the 66rc from 2005 which is taller than the 2006rc) Travel is only one part of the heigh of a fork.

HA is headangle...in moto terms I am refering to rake.

If the new fork does in fact lower the front end, not only will the bottom bracket be lower, but the head tube angle will increase. This will result in a quicker steering and less straight-line stability.

Al

Agree with Al, but if the courses are very technical, this may work to your advantage.

The general rule of thumb is that changing your fork travel by 1" (approx. 25 mm) will change your head tube angle by 1 degree.

That 1 degree will dramatically affect your bike handling.

Try it out, you may prefer it!

This is kind of unrelated but funny. I just bought a old Marzocchi Z3 to replace a crappy RST fork on my hardtail. The Z3 has 70mm of travel when I went back adn read the reviews on mtbr from 1998 the fact that it had 70mm of travel instead of 60 made it more of a "do anything" fork. People were saying things like, "if your into big drops and stunts go with the long travel 100mm forks, if your into racing go with the 60mm forks." Kinda of funny know that there are race forks with 100mm of travel.

less travel doesn't really mean lower or shorter fork. depending on the model and brand, that might be different. (i.e. a Judy C 80mm is as long as a Fox 100)