Help me build my 69er

[wcoastbo]

I need help from the Collective, some of your brain power please.

My 26" SS needs a change. I'm thinking of buying a rigid fork and converting it to a 69er/96er. The axle to crown length of my SID is approx 18.25" or 463.5mm (measured from the middle of the axle to the bottom of the bearing cup).

Here are my concerns.
1) I don't want to substantially change my geometry
2) I'd like to keep standover height about the same

If I buy a rigid fork that's 440mm, will this address my concerns and still let me fit a 29" wheel with a 2.3" tire? or do I have to settle for a 2.1 tire?

My not so accurate estimate shows that a 29" wheel with 2.1" will fit a 440mm fork, but the 29" wheel will increase my standover height and slacken the head angle (more so with a 2.3" tire).

Here's the fork I'm thinking of. Pricey, but worth it to me if it works. I'd hate to waste my money if it doesn't work well.
www.bikemannetwork.com/biking/p/SSFK/FK1520

[king]

try getting a 26" rigid for suspension corrected for 100mm. as long as its disc specific it might work. either way it will change the geometry and standover a bit.

bontrager also makes a carbon rigid fork. i think i'd prefer this one though:

www.sibexsports.com/forks.htm

pero ang mahal!

[32by18]

go full 29er!

Or try to score a Maverick DUC32 or SC32(i think), and get the 29er spacer kit. Disc-specific, proprietary hub and stem system though.

I think you may still have a problem slapping on a typical 100mm 26er fork, because of the brake arch.

A 29er rigid fork will work, but take a look at the fork offset/trail/rake numbers- these may be able to compensate for the slacker HTA.

[king]

hmm.. the axle to crown pf the pace 29er is 440mm so it shouldnt change the geometry too much if the SID's is 463

[jacklero]

Thre shouldn't be any problems with the pace RC31 though 2.3 might be a a little too close for a 29er riding on the 26" pace forks.

[extraFunky]

My 29er rigid fork is only 425mm a-c and there's plenty of room even for a 2.5 I'm currently running Nevegals, about 61mm tread width on a Salsa Delgado disc rim.

[wcoastbo]

Thanks everyone for the input, very helpful.

jacklero - I definitely think the 440mm RC31 is the safest option for tire/wheel fit, but may alter my ride characteristics.

King - I like those Sibex forks it's my first choice, but you're right they're too expensive for me (I need to save up for a plane ticket). You're thinking exactly what I'm thinking... the fork I need to get is a 26" and has disc tabs. I've found some forks of different A-C lengths and need to dial in the right one.

Agu - The Maverick is sweet (and soooo expensive) and if I were looking to buy a complete bike, the Trek Travis Brown 69er is one of the nicest rides I've seen.

xFunky - If I remember correctly you have a custom WW (sweet bike BTW, I'm jealous). It probably doesn't matter for tire clearance, but do you have a unicrown or segmented fork? I'm not sure the correct way to measure A-C length. I started at the bottom of the race. Did you do the same? If there is plenty of room for a 2.5" tire, then I may be able to use the 420mm Pace. This would give me nearly identical geometry and standover clearance with a 2.3" tire. One more question for you... do you have any toe overlap with the front tire? or is your toptube long enough to compensate for the 29" tire and short fork?

Agu - I'm guessing you don't have toe overlap issues given your frame was designed for 29" wheels and a suspension corrected fork, if I remember pics of your SS correctly.

Here's my homely looking frankenbike that I experiment with. Now try to picture it with a 29" tire and front disc. It handles well and I can climb or descend almost anything without any problems. Using my rough measurements a 420mm fork will give me very similar HT angle and standover (with very little mud clearance). There's no toe overlap now, but that could change depending on the fork rake.

[jacklero]

nice rig...

[king]

only downside to the 69 setup would be you have to bring different size spare tubes. then again, in a pinch you could stretch a 26" to fit 29" i bet that's what jon would do, to save weight hehe

[jacklero]

or go tubeless for both can be a bit pricey though...

[extraFunky]

wcoastbo said:

Thanks everyone for the input, very helpful.

xFunky - If I remember correctly you have a custom WW (sweet bike BTW, I'm jealous). It probably doesn't matter for tire clearance, but do you have a unicrown or segmented fork? I'm not sure the correct way to measure A-C length. I started at the bottom of the race. Did you do the same? If there is plenty of room for a 2.5" tire, then I may be able to use the 420mm Pace. This would give me nearly identical geometry and standover clearance with a 2.3" tire. One more question for you... do you have any toe overlap with the front tire? or is your toptube long enough to compensate for the 29" tire and short fork?

Yeah it's WW segmented fork. I measured from the bottom of the race too. I believe the overall diameter is not affected by tire width. Whether it's a 2.1 or a 2.5, it's all going to be about 29" tall, 2.5 will just be wider and fatter, so for sure, vertical clearance is not an issue.

No, I don't have toe overlap since it's custom I think Walt played around with the HT angle and fork offset so I won't have toe overlap.

[wcoastbo]

Thanks again for the input guys. I ordered a Salsa steel fork instead of the Pace carbon. Hard to justify spending that much money on a rigid fork when experimenting. I'll post pics when I'm done with the install.

I'm not sure how a 96er will ride, but my 26" rigid is pretty harsh on fast and rocky terrain. It's my hope a 29" front setup with a high volume 2.3" tire will be more forgiving. Even if the geometry stays fairly close to original, I have know idea how the bike will handle on the trails I ride. Ride report to follow as well.

[bundokbiker]

wcoastbo said:

Thanks again for the input guys. I ordered a Salsa steel fork instead of the Pace carbon. Hard to justify spending that much money on a rigid fork when experimenting. I'll post pics when I'm done with the install.

I'm not sure how a 96er will ride, but my 26" rigid is pretty harsh on fast and rocky terrain. It's my hope a 29" front setup with a high volume 2.3" tire will be more forgiving. Even if the geometry stays fairly close to original, I have know idea how the bike will handle on the trails I ride. Ride report to follow as well.

This one? It's going to definitely jack up your bike. Did you also consider the extra 1.5" of height you'll get from the wheel? Worst case scenario is that you'll need to get a new Mariachi frame to go with it.

[wcoastbo]

I purchased the 26" version of the fork (I've been assured by Bikeman that a 29" wheel will fit just fine). It has an axle to crown length of approx 420mm per Bikeman tech support, this is much less than the SID fork I currently have on the bike.

With the shorter fork and taller wheel/tire, the bike should be very close to original geometry. The tire I purchased is a Kenda Karma LR3 2.2", it has short knobbies. If there's plenty of clearance, I'll purchase a larger volume tire with taller knobbies. I can't wait, the anticipation is killing me... the fork should show up tomorrow.

[wcoastbo]

The 96er is done... the latest version of my ever changing SS frankenbike. A true mismash of parts. Nothing matches! For purely aesthetic reasons, I will change the rear tire to an all black version.

As you can see by the before and after photos... the geometry didn't change much, standover height increased by only a few mm's. The front tire is much closer to the pedal, but no toe overlap. The project turned out exactly as I expected.

Report after 1 ride :

Climbing characteristics didn't change much. I did have less leverage when standing on steep sections, but that was due to putting a 1" stack of spacers under the stem. I'll probably remove 1/2" of the spacers and see how it feels. Raising the stem did feel comfortable on downhill sections, or could that have been from the bigger front wheel making it easier for me to roll over rocks? I'm not sure.

Fast rocky sections transferred a lot of vibration to my arms compared to my old SID, but that's expected with a rigid. Changing to a 2.3 or 2.4 inch tire might take off some of the sting, for now I'm ok with a 2.2 inch tire (most of the trails I ride won't too many long, fast, rocky, downhill sections).

I rode a singletrack trail that was very familiar to me, I was instantly at ease with the new front end. It's a fast, slightly downhill trail, with turns and bump/dips that have great flow. I felt fast. I didn't feel like I had to "learn" how to ride a rigid fork. SIDs are not plush forks and I always lift my front end over rocks/ruts/roots instead of plowing over them, this helped in my transition to rigid. I'll try a trail that has rock gardens, but I'm sure they will be just as fun with a rigid.

Fun factor: very high. You will have to pay attention to the trail. If you hit a sharp edged rock or rut at high speed... there's no suspension to bail you out.

96er tip: it seems a 420mm rigid fork can be swapped with a 80mm travel suspended fork and will give you close to the same geometry, with plenty of room for a fat 29" tire. if your fork has a 100mm of travel, then use a 440mm rigid.

I highly recommend a 96er to anyone looking for something new to try.


frame: generic Ti 17"
fork: Salsa Cromoto rigid 26" (420mm axle to crown)
seatpost: American Classic Ti
stem: generic Ti
bars: 27" Pazzaz DH carbon
cranks: XT Hollowtech II
pedals: Eggbeaters
chainring: Surly stainless 36T
cog: Shimano BMX 20T
brake levers: XTR
fr brake: BB7
rr brake: XTR V
fr wheel/tire: XT, Salsa Delgado 29", DT Swiss/Karma
rr wheel/tire: Mavic Cross Max/Panaracer XC
brake housing: Nokon

[king]

nice, bo! yeah, get another karma for the rear. that's a great tire. i'm currently running a 2.0 in the front and 1.95 in the rear for a little more mud clearance. bring that baby over when you finally get to come home!

[wcoastbo]

Thanks king! When I first converted it to SS I never realized it would be my main mtb... two years later it has become the bike I ride 95% of the time. It doesn't have any exciting or exotic parts, but for some reason it's become my favorite ride.

[bundokbiker]

So how are you liking it so far? Better or worse than with the shock?

[wcoastbo]

I've been riding SS with a SID for two years now and have loved every minute of it. I have about 50 miles on the rigid 96er and my first impressions are very positive.

Stability: Compared to the old setup I feel more confident at speed on fast downhill fireroad sections and flowing singletrack that's not too rocky or has tight switchbacks. I feel faster (no computer, purely assometer readings) and can still out-ride many people on the trails that have FS bikes.

Traction: Front tire seems to track better and has improved traction on turns. I'm not sure which to attribute, 29" wheel, rigid fork or Kenda tire (32-35 psi). Probably a combination of all 3. Overall, I feel like I can push the envelope a bit more on high speed turns.

There are several other trails I want to ride before a review of my new setup is complete... sections with rocky/rutted singletrack climbs, steep rocky descents and tight technical switchbacks.

Do I miss front suspension? Nope not yet, but few of our local trails require FS. I even did a drop to flat at medium speed and it was not harsh one bit... but it was only 18".

Why didn't I go full 29er? My setup was inexpensive and easy. In the future, when I can score a sweet 29er Ti frame on the cheap, I'll add that to my collection.

[bundokbiker]

I pulled out my 26er tonight after spending most of my saddle time on a 29er for the last couple of years. I noticed immediately how it felt "twitchier". The bigger wheel's gyroscopic effect is very noticeable and I've grown to like it.

Have fun with your 69er. I've experimented with them myself and they're a lot of fun.

[wcoastbo]

Yup, I must be feeling the increased stability from gyroscopic effects of the big wheel. I'm comfortable at high speed.

Question for the rigid riders out there. Now that I've ridden several high speed rocky trails, the inside portion of my elbows are sore. I don't think it's the muscles, my upper and lower forearms are strong from all the SS climbing I do. I don't believe the joint is the problem. It must be the tendon.

It started after 3 or 4 rides and has been sore for almost 1 week. Wrist curls are a bit painful, but fully extending my arms and bending my wrists backwards (fingers up) is when I experience the most pain.

Could my tendons be sore from gripping the bars too tight and being to tense while bombing through the rocky sections? I must be transfering a lot of stress to my elbows. How long until the pain goes away? I have to ride my geared bike with suspension today... I don't want to do more damage.

I've never felt pain in the area before, but I've always had front suspension.

[bundokbiker]

wcoastbo said:

Could my tendons be sore from gripping the bars too tight and being to tense while bombing through the rocky sections? I must be transfering a lot of stress to my elbows. How long until the pain goes away? I have to ride my geared bike with suspension today... I don't want to do more damage.

I've never felt pain in the area before, but I've always had front suspension.

When you are riding rigid, the most important thing to do is to learn to relax and stay more fluid. The grip of death is, well, bad. If you tense up, the shock travels straight through your arms and into your body.

Although hardly typical of all my riding, I typically love this kind of riding:

[wcoastbo]

Thanks, good advice. I thought I was pretty relaxed when suspended, but my true death grip self seems to have emerged while riding rigid. Riding rigid really shows where I picked up some bad habits. Let's see if this old dog can learn some new tricks, or unlearn some bad ones.

Riding suspended really does hide bad technique. I truly believe a good way to improve is to ride rigid. I won't give up suspension, but when I do go back to suspension I will be faster. Same as SS, I didn't give up gears (I have them on my road bike) but I'm faster and stronger from riding SS.

[king]

looks like you beat Dirt Rag to the punch:

Making Your Own 29/26er
www.dirtragmag.com/print/article.php?ID=860&category=features

[wcoastbo]

Good find on that article. The author did a much better job explaining the benefits of 96ers than I ever could. Even with less than 10 rides on my newly configured bike, I truly believe in the merits of the big front wheel. Especially with a rigid bike. I'd like to try it out on a suspended bike and that Ibis SilkTi looks pretty sweet.

[king]

here's a little more on 69ers. Trek is producing the singlespeed Travis Brown has been using last year, and will be introducing a FS version as well (geared here with a 9 speed transmission, but a single ring up front)

www.velonews.com/tech/report/articles/12045.0.html