Mountain Biking - Replacing suspended fork with rigid

I have a Cannondale F400 that I purchased used from CL. In the last few months, I've upgraded to Avid disc brakes, a full Sram X5 drivetrain and new wheels. The bike is great, with the exception of the fork. It came with a 100mm Manitou Elite which is a crappy, low-end coil fork with little adjustability and which is very heavy, and it affects my ability to lift the front end over roots and things. I can't dial in the rebound properly, and it's the worst part on my bike.

I don't have very much to spend on a new fork, and most of the used forks I've seen on eBay in my price range (~$100) seem old, leaky, or just as crappy as the fork I have now. I was thinking about a rigid fork with disc mounts, like the Surly Instigator (http://surlybikes.com/parts/instigator_fork/). It's 100mm suspension corrected, has disc mounts, is black like my current fork, and seems sturdy. Prices vary from $65-75 brand new, which is nice. It weighs about 3lbs, which will probably save me about 2lbs over my current fork, which will surely be a big improvement.

My question is how much more difficult is riding technical rooty trails on a rigid bike vs suspended? Bear in mind, the rigid fork is competing with one of the crappiest suspension forks made, so will it be noticeably more difficult to maintain control? I live in Oklahoma, so downhill is not an option, but I usually ride on very twisty single track. If anyone could share a similar experience with the transition, I would appreciate it. Who knows? If I like it, I might try out one of those rigid 29ers w/BB7s from BD!

. . . and which is very heavy, and it affects my ability to lift the front end over roots and things.I don't question anything about your desire for a better fork; but I had pause at this statement. Seems to me you need to work on technique rather than blaming the fork. I routinely lift a 7 lb. dual-crown over trail obstacles, and I am by no stretch of the imagination a burly guy.

i would bet if your rode the rigid fork for a while you will become a better rider and be able to use the suspension better since you won't be trying to just blast over the things in front of you. Just how i see your post atleast. To answer your question riding rigid is not more difficult from my experience (on what seems to be like trails like i ride) it's just a different feeling/mind set. You will pick more smooth lines because you know you have less gnarsquish to take the bumps.

I don't question anything about your desire for a better fork; but I had pause at this statement. Seems to me you need to work on technique rather than blaming the fork. I routinely lift a 7 lb. dual-crown over trail obstacles, and I am by no stretch of the imagination a burly guy.

Well, all I know is that the front end of my bike feels much heavier than other bikes I have ridden. I rode a buddy's GF with a Marzocchi air fork, and even a FS Stumpy 29er with a Reba. They both feel so much lighter on the front end, it's incredibly easy to get them up over curbs, roots, etc or to bunny hop them too.

I don't know if the geometry of my bike could lead to a greater feeling of weight on the front end. It has a very sloped top tube that runs in a straight line from the steerer tube junction through to the rear dropouts, kinda like most DJ bikes. I just know that cutting 2-3 lbs off the front of my bike will make lifting over obstacles, especially on inclines and declines, somewhat easier.

A rigid fork actually corners better because the front end doesn't dive. It also helps you keep your weight over the rear tire when descending steep trails for the same reason. Where a rigid fork sucks is when you are going downhill at high speed and there isn't a smooth line through the rocks or roots. Then you just have to get loose and try not to have your eyeballs jarred out of your skull (or ride slower). Running fatter tires at lower pressures will help take some of the edge off. Personally, I think you are on the right track - I would much rather have a rigid fork than a crappy suspension fork.

Running fatter tires at lower pressures will help take some of the edge off.

The Surly forks allow clearance for 2.7" tires. That's a lot fatter than the 2.1" I'm running now. I could get some fatties to help out. Anyone have a recommendation on a fatter tire for rooty singletrack that is relatively hard packed?

I'm looking at the Surly 1x1 as well as the Instigator. The 1x1 is a bit cheaper, and is also quite significantly lighter: 1030g vs 1420g for the Instigator. However, the 1x1 is suspension corrected for 80mm travel where the Instigator is for 100mm. Do you suppose 80mm is enough, or will I notice a significant difference in the geometry? Also, what effect does the axle-crown distance have on tire fit and geometry, given the same size tire? The Instigator has a distance of 447mm vs 413mm for the 1x1.

A rigid fork actually corners better because the front end doesn't dive. It also helps you keep your weight over the rear tire when descending steep trails for the same reason. Where a rigid fork sucks is when you are going downhill at high speed and there isn't a smooth line through the rocks or roots. Then you just have to get loose and try not to have your eyeballs jarred out of your skull (or ride slower). Running fatter tires at lower pressures will help take some of the edge off. Personally, I think you are on the right track - I would much rather have a rigid fork than a crappy suspension fork.

I am all for rigid forks, but I don't know about that one.............

OP.........measure your current AC height (while on the bike if possible to account for sag)

Compare it to the AC heights of the rigid forks.

Its probably closer to the 1x1 due to sag.

you are probable in the middle of the two, right?

OP.........measure your current AC height (while on the bike if possible to account for sag). Compare it to the AC heights of the rigid forks. It's probably closer to the 1x1 due to sag. You are probable in the middle of the two, right?

I'm assuming that the correct measurement is this right?

http://dl.dropbox.com/u/168335/ac%20measurement.jpg

So you're saying that with me on the bike, due to sag, the AC is probably closer to 80mm that 100mm, so the 1x1 should be roughly as close to current geometry as the Instigator?

EDIT: So I haven't measure my fork, but I found a AC height table (http://www.bikeradar.com/mtb/forums/viewtopic.php?p=14760329) (for Axel Elite) that said mine should be about 480mm. So even if my fork sagged 40mm with me on it (or 4/10ths of the total travel) it would still be right at the Instigator height, and 34mm off of the 1x1 height. I'm starting to lean towards the Instigator, no pun intended.

It sounds like you have your answer

I'm looking at the Surly 1x1 as well as the Instigator. The 1x1 is a bit cheaper, and is also quite significantly lighter: 1030g vs 1420g for the Instigator. However, the 1x1 is suspension corrected for 80mm travel where the Instigator is for 100mm. Do you suppose 80mm is enough, or will I notice a significant difference in the geometry? Also, what effect does the axle-crown distance have on tire fit and geometry, given the same size tire? The Instigator has a distance of 447mm vs 413mm for the 1x1.

If you're looking to go rigid, 29er is definitely the way to go. I rode for 3 years on a rigid 29er (Karate Monkey). Unfortunately, I'm a hard riding 280 pound guy and a took out two Karate Monkey frames. So I decided I needed a suspension fork to try to preserve the frame I'm on now.

As fate would have it, I suffered a serious shoulder injury 1 week before my new frame arrived. It came in handy. It also came in handy when I was at Brown county state park. If I had my druthers, I would be on a rigid fork. But it's not in the cards for now.

Just remember it will take you a while to get used to a rigid. You will now have to exaggerate movements and do the work your rigid WAS doing for you. Good luck.

Thanks Thor,that made my day. I LOL'd out loud..( I would have replied w/quote but this suck @#$ new system woun't let me).

I am all for rigid forks, but I don't know about that one.............

Yeah, sure the rigid fork doesn't compress much but, it sure as **** causes the tire to skip and jump around on the ground a lot.

So, no.. nothing inherent about a rigid fork makes it better suited to off-road cornering.

Don't blow smoke up my ass! :eek:

I got rid of the Dart2 and put these switchblades on my Kona Blast.
http://img.photobucket.com/albums/v353/bbrace/005.jpg

i recently got a white surly 1x1 fork and besides looking sharp it works better than my 2001 marz.bomber which has like 10k miles and 1 rebuild. the fork is lighter and on technical trails uphill its so much easier to ride. downhill is a bit more sketchy but im becoming a better rider. the 1x1 fork is like 65 bucks new and i got it for 30 shipped barely used, so i cant complain. unless you ride a good fork with lockout, i would ride rigid on a ss.

I am all for rigid forks, but I don't know about that one.............

That (what you responded to) is an absolute incorrect statement. If you don't know how to use your suspension then yes, it simply dives. But if it is setup correctly in rough terrain it should in fact track better than a rigid. A rigid will have no give in the rough stuff...