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Discussion Starter · #1 · (Edited)
Just finished building a new bike for my mom (replacement for her '97 Mantra Comp built w/ King+Mavic 517 28h wheels + Full 8sp M950 XTR).

There were three goals:
1. Flawless shifting
2. Light weight (her current bike is in the mid 24# range)
3. Low maintenance

The basic ingredients were to be:
-'97 Klein Mantra Pro frame w/ Cane Creek air/air shock (5 lbs 6 oz) The URT design also allows for simple torque arm mounting (no pivot between the dropout and chainstay) as well as a fixed chain tensioner!
-Rohloff Speedhub (laced by Dave Thomas at SpeedDream.com)
-Lightweight Fork (originally going to use a Fournales Shark XC but this required a custom headset w/ bearings recessed in the frame to achieve the desired stack height ... good winter project).

It took 11 months and 2 weeks from when I received the first component till I took her out for the debut ride. It's hard to find exactly what you want (spot chairings, ride on cables, klein stratum 90 bars (still not found)) ... especially if you're trying to find it in good shape at a decent price on ebay!

Here's the result:
http://homepage.mac.com/dgiessel/.Pictures/misc/97_pro/index.html

As shown, 25 pounds 3 oz. Some components will be changed. They are as Follows:
Rennen tensioner will replace the Soulcraft. Friction mounting (one bolt) a fixed tensioner just doesn't work in the pulling position, and even with a half link the chain is *just* too long to push it up. A 15t rear sprocket would solve this issue, but the Rennen is superior anyway, and the hub is bolt on so who cares about having a button to release chain tension.
Cane Creek DC2 brakes will replace the DC3s. The DC3s are scarily wimpy. The Weinmann 999 brakes on my '73 Raleigh Grand Prix honestly work much better, and that's on chrome steel rims! This swap will add a few grams, but not much.
I have to make a clamp for the Rohloff torque arm. It's currently zip tied in place (quite well I might add), but I'll have a proper clamp on there soon enough. The fat Klein chainstay has a pretty large curcumference so the Rohloff unit didn't stand a chance of fitting.

Anyway, with a bit of titanium hardware here and there and stuff like a Thomson Elite stem, lightweight seat collar (tho she'll need the QR to get the bike into her car easily with the rear wheel bolted on), lightweight chain, M950 BB, etc ... this sucker could dip into the 24 pound range quite easily. Oh, there are a lot of pedals out there that are lighter than my trusty old 747s too!

Some notes. I have been stocking up on Gore RideOn cablesets ever since they quit making them so many years ago. This bike being so special (at least in my mind) received a highly cherished "ultralight" cableset with fiberglass shift housing to shed a few extra grams. The brakes also got RideOn treatment and with careful attention to keeping the grub worms on the business ends of the cables, I expect that they'll operate friction free for years to come. I think sealed cables are a must on a gear hub bicycle. While the indexing takes place in the hub, it's still important to keep shifting effort and cable drag low in order to maintain precise gear changes. My basic problem with derailleurs has rarely been the deralleur itself (other than a twig sticking in the rear now and then ... or chainsuck of course), but much more often due to the cabling getting so mucked up that there's too much friction for things to index (or even move). Isn't this one of the reasons why we all love our hydro disc brakes so much too? Anyway, sealed cables almost convinced me to keep my 8sp XTR stuff on my bike, until I had the rear der. wrap up all the way around the cogset and make the most of the fact that my frame has a replaceable rear der. hanger! Another Rohloff please!

As far as how the bike/Rohloff rides ... I was keen to see how the change in weight distribution (and primarily the increase in unsprung rear weight) would affect the Mantra. I've been on these frames since 1999 now and have tried a bunch of different configurations (from 31 lbs with coil shocks and heavy wheels/2.35 tires to 24 lbs with air shocks and light wheels/1.95 tires) so I felt like I had a pretty good baseline. I did a little 35k loop on what I'd describe as rolling singletrack (with a lot of roots) and didn't notice the weigh shift one bit. Even on the occasional quick little rise (with a super light front end I might add) there were no balance issues. Perhaps this is because the Mantra begs its rider to bias a lot of weight over the rear wheel anyway, so my riding style masks the rearward weight shift? I did feel the extra pound back there when bunny hopping, but I don't think it reduced my (rather limited) vertical leap. The bike as a whole is so light tho, that it doesn't even "feel" heavy when you pick it up by the seat (the balance point is not far off where my derailleur equipped Mantra's is).

The suspension feels great (just as good as the AD-12 on her Comp felt when it was my Comp). The Cane Creek air-air shocks are so good over high frequency bumps (as the damping is proportional to the size of the bump, so they have really fast response on little stuff) that any extra inertia caused by the hub goes largely unnoticed. On some bumps the rear wheel does land with a slightly more authoritative "thud", but I've noticed no detriment to ride quality or traction over bumps (again, the fact that the Mantra biases rider weight so far over the rear wheel probably helps in this case). For reference my Mantra has a American Classic 26 Disc rear wheel with an M900 cassette, M952 mid cage rear der., Hayes V6 rotor (w/ ti bolts), and bolt on skewer ... so it's about as light a rear end as you can get.

As it stands, if I were serious about XC racing, I would build exactly the same setup for myself (with a large 99-01 carbon frame tho, as the 97 Pro was only built in medium). The hub was purchased used, so it's already pretty smooth. The drivetrain loss penalty is small (but noticable) compared to my new chainring, new cassette, new chain XTR setup, but never having to stop and resolve a chainsuck/dropped chain issue buys that time back and then some (what's the drivetrain efficiency when you get off your bike and watch your heart rate crash then spike when you stop to resove the dropped chain then try to make that time back?). I guess if you race on clay or smooth trails, you'd not see this advantage as often. Anyway, this thing feels really fast, regardless of what gear you're in, and there's very little weight penalty over a "modern" top of the line derailleur equipped FS rig.

Here's a detailed list of the components:
97 Mantra Pro Build Component List
Frame: 1997 Mantra Pro Medium
Tires: 2003 Michelin Comp S Light
Tubes: Bontrager XXX Light (med valve stem)
Wheel (f): White QR hub, 28 Sapim 2.0-1.5 butted spokes, Alloy nipples, Bontrager Valiant 28h rim (non ceramic), Lightweight rim tape
Wheel (r): Rohloff Speedhub 500/14, 16t cog, 32 Sapim 2.0-1.5 butted spokes, Alloy nipples, Bontrager Valiant 32h rim (non ceramic), Lightweight rim tape
Wheel Mount: Rohloff Torque Arm w/ steel chainring bolts, Rohloff steel axle bolts and split washers, steel hub hardware (torx screws)
Skewer (f): Generic bolt on w/ steel bolt
Brakes: Cane Creek Direct Curve 3, steel hardware
Brake Levers: Cane Creek Direct Curve, steel hardware
Grips: Generic left, Cane Creek bolt on right
Handlebar: Easton CT70, stock length
Stem: Bontrager wrap around 90 x 7 deg, steel hardware, 1x 5mm shim
Top Cap: Scott alloy, titanium bolt
Headset: Reset Racing MC3 conversion
Fork: 2007 Rockshox Sid Race w/ 7.75" steerer, steel star nut
Saddle: Terry Butterfly Ti
Seatpost: Thomson Elite 31.6 x 410 mm
Seat Binder: Gary Fisher Quick Release, steel hardware
Shock: Cane Creek Cloud 9, 7.875" eye to eye w/ steel mounting bolts
Cranks: Shimano M950 XTR, 175 mm, stock self extracting alloy bolts
Pedals: Shimano 747 w/ original Cr-Mo spindle
Chainring: Spot Brand 34t one piece alloy
Bottom Bracket: Shimano M952 112.5 mm spindle, 1 mm steel shim on drive side
Chain: SRAM PC58, 44 full links, power link, half link
Tensioner: Soulcraft "The Convert", delrin pulley shim only
Cabling: Gore Ride On Extra Light shift cables, Gore Ride On brake cables, Rohloff "internal" rear hub cabling
Shifter: Rohloff Speedhub twist shifter

Comments are welcome (and appreciated!)

-David Giessel
 

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Nice build ! :thumbsup:
You mast have a happy mom !

I would add to the Rohloff advantage ; when your stopped in a climb and you just downshift and go ! ( don't have to lift the rear wheel , shift , pedal then go )
 

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Interesting build. The Rohloff is an interesting piece of kit, and that's a stellar build with one.

As to your brake problems, why not go XTR V's instead of the Cane Creek DC3's, the Prallel-Push V's work very well and are reasonably light.
 

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Nice build! I've been keeping my eye out for one of those with the chainstay disc mount for a Rohloff build, we never saw many of those around here. I have a long term plan to build up a BowTi with a Rohloff.

papercutninja said:
My OCD is bothering me. Why the mismatched grips? ...
It's hard to find matching grips, since you only have one shifter. My wife's bike has one yellow and one red grip - just to accentuate the difference.
 

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Hey Tycho, small 'net! I recognize you from some of the Mac forums. ;)

Sweet ride you put together there. Your Mom must be the coolest Mom in your town. :thumbsup:
 

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Discussion Starter · #8 ·
Thanks for the feedback :)

I actually had a set of XTR V's this spring but they got built up on my "loaner" Mantra along with an assortment of other M950 stuff I'd accumulated over the years. I wanted to give the direct curves a shot because they are very light, probably don't squeal as much (no linkage) and also because the cable routing is ultra clean (no noodle). I'm still holding out hope that the DC2s with a little extra meat will stiffen things up sufficiently. I'll say that the DC levers are really nice units. Right up there with the XTR ones on my STI pods (if I had a set of jsut the XTR levers I would have used them).

It's true the grips are sort of goofy. I guess I don't worry about grips too much. Maybe it's because I put most of my miles on the aforementioned old road bike, which still has vinyl tape! Having the lock on grip on the twist shifter side seemed like a good deal to me as that grip has less surface to bite on the bar and may also see a bit of extra "twist" from the shifting action when one's hand isn't all the way over. With my gloves on I don't notice the difference in the grips. At least not as much as the difference in brake lever reach as a result of having only a single twist shifter. If she complains I'll buy a identical "short" and "long" lock on grip sets and make a "matched" pair for her. I guess I'll need such a set for myself by next spring too...

I put the Rennen Rollenlager on today and it's a very nice unit. I actually ordered two when I discovered its existence as I knew it was *perfect* for the job at hand (and I'll need one myself soon). I was especially pleased to find that since it is longer than the Soulcraft, I can use it in the "push up" position without having the pulley hit the chainstay! One thing to note about it (and all non toothed pulley type tensioners) however is that since most half links are slightly "taller" than a regular chain link, you'll have a tight spot every time the half link plates go over the roller (not an issue with pulley type tensioners as they ride on the chain rollers, not the plates). I may fix this with the dremel as I don't think my mom is going to have problems with broken links. Another thing about the half links is that even the 3/32" ones are just a hair too wide to use with a SRAM power link. Again, I was able to squeeze the plates just a tad closer together and trim the bushing to the right width, but stuff like that is what makes these projects take so long (like the dropout/axle plate work that had to be done to get the hub to fit). I'll add pics of the tensioner to the gallery linked above when I get a chance.

Were you a lurker on the XYM forums chucko? It's been a couple years since I've visited that site. Based on your location, you wouldn't happen to be an Apple employee?

Anyway, I just brought the bike to its new owner tonight and we're going out to do the Gull Rock trail in the morning. I'm eager to see how she likes the Speedhub!
 

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Tycho said:
Were you a lurker on the XYM forums chucko? It's been a couple years since I've visited that site. Based on your location, you wouldn't happen to be an Apple employee?
Affirmative to XYM (very occasional poster), negative to working at the big fruit.
 
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