Front fork dropouts
 

I'm looking at this rigid length-corrected front fork to replace my weak RockShox fork: http://www.nashbar.com/bikes/Product...0052_174928_-1

The specs say "9mm dropouts". Does that refer to the width of the slot for the front hub axle? Or is that the thickness of the metal at that point? I know the metal thickness of my RockShox forks is pretty thick at the dropouts, could be between 1/4" to 3/8" thick (will measure this evening).

If the metal thickness at the dropouts are considerably different than my current fork, will I have to change out my front quick release skewer?

I did check the axle to crown length of 453mm on the rigid fork, which almost exactly matches the unloaded length of the RockShox fork.

Yes.

9 mm is the standard diameter of the front axle. Older (english?) bikes and kids bikes can be narrower, some AM/FR/DH MTBs use thicker.

then, in theory, it's too long. ATC of the rigid should be about the same as the ATC of the sus fork when you're on the bike.

Regarding the 9mm, I believe that is to differentiate it from the newer through axles seen on MTBs now. Virtually all modern bikes (without through axles) use 9mm axles, so you have nothing to worry about. Your QR skewer should have plenty of threads.

+1 I would look for something a bit shorter if possible. A smaller ATC will make the handling a bit "quicker" and probably liven up the bike nicely. Otherwise, I wouldn't consider it a deal breaker.

Well right now my front fork is so weak that it sits bottomed out the whole time while riding in the saddle on flat ground. Then it pitches up and down if I'm really pounding it up a hill. It feels like the whole bike is tipped forward when riding with the fork bottomed out.

Well crap now I don't know. I measured again and 453mm measures from the axle on my RockShox to the very top of the bottom blue ring of the King headset, i.e. from the axle to the very bottom edge of the yellow head tube:

http://img.photobucket.com/albums/v3...e/IMG_5330.jpg

I don't know if the Nashbar fork's 453mm is from the axle dropouts to the very base of the steerer tube or what.

"Crown" should be read as "crown race seat" which is the very base of the steerer tube, as you call it. Swapping in a rigid fork the same length as an unloaded fork is likely to result in a bike that feels sluggish. Still rideable though.

You should be ok. Skewers are fairly well standardized these days. The difference in thickness is because your suspension fork lowers are magnesium or aluminum, whereas your replacement fork is steel. However the difference in thickness should be within tolerance. I would be surprised if your current skewer didn't continue to do its job.

You're over thinking it. Even if it's off compared to the stock fork, the difference in feel between rigid and sprung will be so much more noticeable than a fraction of a degree taller or slacker of head tube angle. By the time you can evaluate the angle, you'll already have gotten used to it.

FWIW, I tend to agree. I've put rigid forks on various frames. I've actually found myself installing the Cane Creek S3+5 headsets a couple of times to try and increase the axle-to-crown. Most of the time I am wanting more, not less. Most recently, I put a Surly Instigator fork corrected for 100 mm onto a frame designed for an 80mm fork. That's worked out *very* well, and the resulting 26er rigid has surprisingly become my go-to bike so far this season.

Alright cool. So basically the fork I'm looking at will be about 10mm longer than my current fork's unloaded length.

I know it sounds bad, but I wish there were a way to sort of "jam" something in the middle of my front fork to effectively lock it out and keep it fully extended, just so I can feel what it's like (it has no lockout function).

Well...

If you're all set on scrapping it, you can always try putting jubilee clips/hose clamps around the upper legs in the extended position. While not recommended for regular riding, it should be enough for a sedate experimental cruise around the block.

A peice of wooden dowling the same length and diameter of the stock spring will keep your forks nice and stiff. A rigid fork will be lighter and look a lot better than a crappy old suspension fork.

Tiny differences in fork length are not a big issue. THere might be a more noticable difference in handling going from a non-suspension corrected rigid fork to a 2" (50mm) or more lontger suspension fork, but even that is usually not terrible.

Or I could just jam a piece of wood between the cross piece of the lower forks (where the hole is for a fender) and the cross piece where the steerer tube is :lol:

Poor man's suspension lockout :p gonna ride it around like this for a bit just to see what it's like.

http://img.photobucket.com/albums/v3...e/IMG_7961.jpg

That's awesome. Totally saving that picture.