80mm to 100mm fork replacement, Yes or No?

[!TREK4ME!]

Hello,
I have a Trek 4900 with a Rock Shox Pilot C fork that is leaking at the seal. I'm not sure whether I can replace the seals and from a earlier post, it's probably more costs effective to just get a new one. I've got a couple forks in mind for replacement, but have a question:
The original fork is a 80mm... should I replace this fork with the exact size travel fork or can I get one with a little more travel(100mm) and hopefully not mess up the geometry of the bike/ride too much??
I'm a Clyde @ 6'-4" and 275lbs and the original shock was a little soft, but seemed to do alright. I had the preloads adjusted all the way down and had about a 15-20% sag when I put my weight on the bike.
I'm looking to upgrade to a lockout type, ex.--Rock Shox XC28 100mm or maybe a XC30, not sure yet.
What do you guys think??
Thanks,
PJ

[Painkiller]

1in. or 1 1/8 steerer tube? With a 1" steer you will have little to choose from, either way there is not much in an 80mm to choose from unless you found a new old stock fork
http://www.ebay.com/itm/ROCK-SHOX-FORK-1-1-8-JET-THREADED-STEERER-MOUNTAIN-BIKE-SHOCK-NOS-/350814586859?pt=US_Forks&hash=item51ae2dc7eb
threaded or not?
you could possibly use the guts from one like this. But you should be okay with 100mm and with give you a chance to mock up and decide if you want your bars higher or lower before making your cut

[!TREK4ME!]

Thanks for the reply.
It is a 1 1/8 steerer and non-threaded.
So you don't think the geometry with about 3/4" more upright and 3/4" more shock travel will be too drastic on the ride??
Thanks,
PJ

[Painkiller]

you will notice more in how fork rake/offset affects but not much. Frames designed for long travel 120mm and up have more drastic geometry changes than yours. Plus keep in mind that company to company vary slightly in what they deem to be the ultimate angles. in fact they may have offered a 100mm shock on the same frame as yours in a higher priced model. I think you will like the extra travel and not notice much of a difference. Hopefully someone else will chime in, but you are pretty much limited to a 100mm shock for any kind of quality

[!TREK4ME!]

Awesome !!
Any shock you would recommend that might do better for my application and please explain.... I'm learning.
Thanks a bunch for the help !!
PJ

[Painkiller]

(06-23-2013, 09:37 PM)!TREK4ME! Wrote:  Awesome !!
Any shock you would recommend that might do better for my application and please explain.... I'm learning.
Thanks a bunch for the help !!
PJ

disc or V-brake compatible? price range?

[!TREK4ME!]

v-brake... $125.00 to $200.00 price range... maybe a little more.

Thanks,
PJ

[Painkiller]

(06-23-2013, 11:54 PM)!TREK4ME! Wrote:  v-brake... $125.00 to $200.00 price range... maybe a little more.

Thanks,
PJ

plain and simple, in this price range they are about equal. some like the suntour and some like the rockshox. I saw on ebay a couple you mentioned already at a decent price. for moderate light path and trail use is what these are really designed for despite being sold on entry to mid level hardtail/full suspension bikes. True off-road forks cost hundreds. so go where your wallet takes you.
http://www.ebay.com/itm/261234882631?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
even rst brand are better than they used to be. I would go with one in the link, it is priced decent and free shipping.
the important thing is to mock the setup before cutting the tube to get your bar the height you like, figure twice cut once is the rule. the park tool saw guide is nice also

[!TREK4ME!]

Awesome !!... Thanks !!

Just happened to look at the Rock Shox website. Was comparing the XC shocks. Noticed that the 28mm TK comes 80/100/120mm travel. Is this adjustible or do you have to let them know which one you want?? Should I stay OEM(80mm) or go 100mm??
Also, looks like it comes in light, firm, extra firm springs. How do you know which one you need or you are getting. Does it say it on the box??

The XC 32 TK comes in 80, 100, 120mm but is solo air. Now, with this one I would use the air to get the firmness I want, right??

It looks like they are also available in different steerer options too: 1 1/8" STKM steel, aluminum; XL 1 1/8" steel and aluminum, etc. Which one should I get??

Sorry for all the questions... I'm learning.
Thanks,
PJ

[Painkiller]

with the specifics of questions your best bet would be to talk a rockshox tech to be more accurate. there are charts to guide you to settings and air pressures to play around with and are merely guides without total absoulute. some shocks have dual travel settings on the fly, I would think the 80mm fork to a separate fork, again speak with a tech to be sure. A lot of it has to do with how much you weigh and purpose/style of riding you intend to do. The stkm steel I believe is a high carbon seamless tube, aluminum or steel will be fine.
http://cdn.sram.com/cdn/farfuture/4zMnbTWiq0CmxYvi0VeYYWLF5C2HoGzQg_4xKIMk7-E/mtime:1369345767/sites/default/files/techdocs/gen0000000004392_rev_a_rockshox_oil_air_and_coil_chart_2014_0.pdf

comb thru these to get an idea

[!TREK4ME!]

Awesome !!.... Thanks !!!!!

[tourgee07]

hay, personally..if it were i i would do the 80mm..stay oem if possible, i had an older specialized rock hopper it had 80mm travel rock shocks..i traded for 100mm with a buddy..he had a slack frame design trek dont remember the model of his..but i thought i would love a bit more travel..wasnt fun, because of the frame design it jacked the front up like 3/4 inch which shifted my weight differently..the bike went from feeling stable with the 80 to squrilly with the 100, to fix the squirilly feeling i switched the tires from 1.95s to 2.1. and ran a lower tire pressure. it helped a little..but was agravating..eventually i sold the bike cause my friend wouldnt trade back..in short "geometry makes a difference!"