mosk

I'm building a new MTB, my first in 10 years. This will be an XC bike for trail riding and singletrack (no racing). The bike will be built around an older (ca. 1997) Fishlips/Titus ti hardtail frame. Frame is medium sized, and I'm 5' 8". I want a bike that climbs very well; I won't be pushing this *too* hard on the descents, as I'm now 41 w/two kids and presumably know better.

I really like everything I've heard/read about the Fox Terralogic forks and plan on using one. My question is an old one: the frame was probably built for an 80mm fork, and I wonder how sluggish it will steer and/or how much less climable it will be with a 100mm fork. I realize that for 90% of the stuff I ride the two forks will probably behave similarly, so the question is really about that final 10%: how much climbing/steering ability do I sacrifice by slacking the head angle by 1 degree, vs. how much additional descent capability do I gain with the extra 20mm of travel?

If this were your project, which size fork would you go with? I don't plan on hammering this bike down much stuff, but both forks are the same price and an extra 20mm of travel for the same price sounds tempting. At the same time, I plan on owning this bike for at least 10 years, so I want to make the best decision possible.

Advice?

Thanks,

Jeff

sparks_219 

I would get the F100x and use a lower stem/bar. If the 100mm is indeed too much travel, you can easily convert the fork to 80mm travel.

Good Luck

mindbogger

I would stick with the 80mm to keep the geometry the same. At the same time, what kind of trails do you ride? Do you really need the 100mm?

sparks_219 

Why not go with the 100mm when its the same cost, weight and the 100mm is easily converted to 80mm??

mosk

Is the 100mm easily converted to 80mm? I don't know if that is a feature of this fork...

As for trails, I'm really not riding much that is extremely technical these days, although I like to venture into some pretty rugged areas (e.g., the backcountry of Henry Coe State Park, south of San Jose, CA). My current bike has an old Manitou EFC with a White Bros. spring conversion, which I think has about 80mm of travel. But it's set pretty stiff for better climbing, and this probably limits the trqavel by at least an inch. With a more capable bike and fork I will probably try some more technical stuff. My current bike isn't the right size for me, and this is also limiting my trail choice. Still, I'm never going to be taking the hardest line, and I'll probably be walking down the sorts of stuff that younger, more aggressive riders seek out -- one of the pitfalls of riding for 15 years and taking a few tough falls...

Jeff

forum*rider

IMO I would just stick with an 80mm fork, it sounds like that will be plenty of travel for what you're going to be riding.

sparks_219 

You have to take the fork apart to change the travel.



There is a pin that goes through the slider, and I'm pretty sure you just push the pin out, and move the slider up and down with the F100X. Dont quote me on that, but I am fairly certain it is the correct procedure.

It sounds like you really want the 80mm for climbing, but the way I'm thinking is, you may want the extra travel for the technical stuff you may be doing, which will be useful. If you really dont like it on the climbs, you can reduce the travel to 80mm for free!

The F100X is also reportedly less problematic with oil leaking, and with its inertia valve compared to the F80X. These problems are however out of the box, and will not bother you once its fixed. I've been wanting to purhcase one of these forks to replace my SID for the last few month, but haven't been able to convince myself to fork out so much cash on a new bike.

If you look closely on ebay, you should be able to get these slightly used for 450, or new "Buy-It-Now" auction go around 550 - 620. I, would buy it new for the warranty. $100 bucks really isn't much in terms of really expensive forks.

Hope you enjoy it

Ming

seely

Even on the craziest descents I've done I have yet to bottom out my F80x. Through technical stuff I think its a huge advantage to not have the front end raked out. With technical stuff, unless you are one of those guys that tries to bash your way through every obstacle, you want quick handling, and if the front is jacked up you won't get the precise handling you probably want. I would definately get the F80x, but thats me. I like climbing so long travel really annoys me. I had a Kona that I put a fork about 20mm too long on and hated the bike everafter for its crappy handling. My F80x got a season on it with no leaks or issues at all.

mosk

Thanks, Ming! Actually, I purchased a new F100X a few days ago through eBay for $500. It's a floor demo and comes with a full warranty...but I was having a little buyer's remorse that I may have spent all my coin on the wrong sized fork. I would like to read more about the convertability of this fork, but the link you posted doesn't seem to work for me. Can you post if again (or post the thread number separately?)

Thanks a lot!

-Jeff

sparks_219 

https://forums.mtbr.com/showthread.php?t=62022

I'd go to that forum and search in the Let's Talk About Shocks sub-forum. The other option is to call Fox, one of their service manuals should give you precise instructions. Please let me know how the fork rides. I may still end up buying a new one next season.

Cheers

Ming

bac

I own two bikes with the F100X fork, and I simply love the fork!!!!!!!!!!

My Bianchi geometry was designed for an 80mm fork, but I like the front end a bit slack for hard, fast downhill runs. I can live with slightly slower handling in the tight stuff if the reward is a much more safe, and controlled downhill run.

My advice is to run the fork on both 80mm, and 100mm to see which suits your riding style better. It's not an external dial, so it will be a bit of a pain to accomplish. However, in the end, you will know more about how you like your bike set-up.

Good luck!

mosk

Great info, Bac -- thanks. So you can confirm that the fork can be setup for both 80mm and 100mm travel?

Thanks,

Jeff

bac

Although I've not done it, the manual states that it can be done. They accomplish this with spacers inside the fork leg. Understand that this travel adjustment is specific to the 100mm forks, not the 80mm forks. Therefore, you can always go down to an 80mm fork with the 100X, but you can never go up to an 100mm fork with the F80X.

BTW, you're gonna love that fork!

mosk

Thanks -- I downloaded the manual and read through the procedure. It does sound possible, but you basically have to disassemble the entire fork to get to the spacers.

This thread (https://forums.mtbr.com/showthread.php?t=57998) and this thread (https://forums.mtbr.com/showthread.php?t=58882) had more info on doing this.

Based on this, I think I'll stick with the F100x. I have a feeling I may enjoy it more in 80mm mode, but as you said, I can try it in each mode and see which I like better, something I won't know until I build the bike.

Thanks, everyone, for all your help. I'm really excited now -- I can't wait to get this bike together, it's gonna be great

-Jeff

Trey

Had you not already bought a fork my suggestion would have been to ask if you had considered a Fox F100 RLT converted to 80mm (same and F100X) and the PUSHed. Push Industries does a stable platform valving that looks appealing. I've ridden the F100X (Just yesterday actually) and think I prefer the platform design concept. I will be able to give a comparison feedback in the spring when i send my Float 100 RLC to them