Questions of rake
Dear Lennard,
I have a 1994 Trek 5200 54 cm. I want to raise up my handlebarheight for comfort reasons. I figure I need to raise it 2 cm.I thought about the Serotta head tube extender. It's titanium, pressedin and adds 2 cm. I would have to buy a new fork. The literaturefor that model year states a 47mm fork rake.I think I could accomplish two things - more comfort and better ride- with the right fork. From a safety standpoint, is this a good idea?If so which fork? Since less rake equals more trai that would make it morestable with same head angle, right? Would a 44 mm rake Alpha Sub Q or 45mm Reynolds or another model with 44 rake? If the bike handled less quickly,I would like that.
HowardDear Howard,
Yes, the bike will steer less quickly and be a bit more stable witha 44mm or 45mm rake (and between those two, I doubt you could tell thedifference).
LennardOne-tooth makes a difference
Dear Lennard,
I recently purchased a new road bike with Dura Ace 10 (7800) cranks.Do you know if Shimano intends to offer 52 tooth chainrings for this crankanytime soon? I realize 53 is the industry standard but I have alwaysrun a 52, even on my modern bikes. If not then in terms of compatibilitywhat chainrings will work best with a full DA 10 set-up?
Nat

Answer from Shimano
Dura-Ace 7800 chain rings are available in 52 and 50 tooth options.Both are b-type rings that are only compatible with the 39 tooth innerring.
Jason W. Leith
Bicycle Components Division
Shimano American Corporation

Ridin' the Big Wheel
Dear Lennard,
I’m seriously contemplating moving myself to a mountain bike with 29-inchwheels.So my first question is, do you buy into the various arguments leveledby the 29er proponents about the inherent superiority of 29ers over a 26er(e.g. – decreased rolling resistance on both rough and smooth trail)?I have been reasonably successful at long mountain bike races (I was thirdat the Durango MTB100 this summer, and 22nd, 17th, and 15th at the Leadville100 in previous years).I don’t want to do anything to compromise my strength – long races withlots of climbing – and it’s darn near impossible to find out if a good29er will help, hinder, or not affect my performance without buying one.Hence my asking the advice of people whose opinion I value.My second question falls into the same category of not knowing if somethingis going to work without a large investment. I continually find myselfdrawn to the idea of a Rohloff internal hub. I realize weight couldbe an issue, but I figure with judicious component choice I could stillbuild up a reasonably light bike. I do wonder about putting all thatweight in one spot however. Furthermore I wonder about the efficiencyof the hub – the Rohloff propaganda says it’s the same as a derailleursystem but it’s not as if you see lots of them out there on XC race bikes.So I am again asking your opinion on something I can’t adequately preview,the Rohloff hub, and its suitability for my application (100 mile racesin the mountains that involve up to18,000 feet of climbing).
PeterDear Peter,
Well, we build 29ers and I believe in them very strongly for tall people,since it allows the bars to be higher, since the 275mm-long steering tubeof most suspension forks is a limiting factor for riders over 6 foot 6inches or so. Having the base of the frame’s head tube be lifted threeinches higher allows the top of the headset to be three inches higher aswell and brings really tall people, who would otherwise have to have alarge drop from saddle to bar, much more comfort and control.Some of the riders I have made them for are well under 6 foot 6 andweigh under 175 pounds, and they love them too. It seems amazing to methat the heavier 29-inch wheel and tire and fork and longer swingarm orchainstays would result in more speed climbing, but everyone who has boughtone from me, whether hardtail or full suspension, says that they climbfaster now relative to their riding buddies with whom they often climbthe same trail.There is no question that the bigger wheels are faster downhill andconsiderably more stable. They also roll over obstacles more easily. Oneof my buddies racing the 24 Hours of Moab this year said that he suddenlyrealized that he was pedaling down a descent on his 29er that he had alwaysjust coasted and hung on in his prior six times doing the race on 26-inchwheels. And the fact that Nat Ross, a small, thin guy, won that race on29-inch wheels is testament to them. You cannot be losing efficiency andexpect to win an endurance test over 24 hours.So I am at least convinced that on balance in an endurance event, a29er is as fast or faster.As for the Rohloff, I can't say. I have never used one. The hub is agood place to add weight if you are going to add it--way better than atthe rim or on the pedals or shoes. A downside is that it increases unsprungweight, making the rear suspension more sluggish. And engineering testshave always demonstrated an energy loss of planetary gears relative toa chain and cog setup, but it is less than five precent, I believe.
LennardTape versus glue?
Dear Lennard,
What is your experience with items such as TUFO tubular tape comparedto glue?I rode tubulars twice in the past for race wheels, but the whole gluingexperience just turned me off to them. So I have been riding clinchers.However, with all the nice new all carbon tubular wheels that are out therenow, I have once again been reconsidering. But I still keep thinkingabout gluing them and it just turns me off.
I'd like to get some feedback on your experience (if any) with the"newer" tubular tapes on the market.
PeterDear Peter,
I have not used the TUFO tape, but I know people whose opinions I trustwho rave about it, and having glued a lot of tires in my life, theconcept greatly appeals to me. That said, in the winter of 1981-1982, whenI was riding cyclocross in Germany, I used tubular rim tape that was availablethen and found it to not stick as well as glue, but I never rolled a tirewith it, despite extremely muddy conditions.For those not familiar with the TUFO tape, it is double-sided tape witha plastic strip covering each sticky side. You peel off one plastic stripand stick the tape down to the rim, fold over a corner of the top plasticstrip so that it sticks out to the side, mount the tire on the rim andinflate it to low pressure. With the plastic strip allowing the base tapeto slip around on it, you can now center the tire up easily without thehassle required when glue on the base tape and the rim is reluctant toyield to your efforts at repositioning the tire. Once the tire is centered,I understand that you can yank the remaining plastic strip out from underthe tire without de-positioning it. You then inflate it fully and can goriding immediately, rather than leaving it to sit overnight for a properbond.My friend Steve Hed swears by TUFO tape, and he certainly has a tonof experience with lots of riders using his tubular wheels. However, everyteam mechanic I saw at the Tour de France and Giro d’ Italia this yearwas gluing tires the usual way, by brushing on glue.Personally, I cannot imagine that the tape can hold as well as a reallygood, multi-layer glue job, and it is narrower than the rim, so it doesnot cover as much surface area as an edge-to-edge glue job. But I haveto believe that it sticks sufficiently well, or I would not hear so muchgood feedback about it. Nobody has told me about problems they have hadwith rolling a tire when using it, and not too many riders have a mechanicto glue their tires for them.
LennardWhat about that tubular clincher?
Dear Lennard,
I wonder if you care to comment on the use of Tufo’s clincher-tubularline. The design sounds like a win-win--capable of high PSI, highTPI, readily repairable with sealant--all with the convenience of a clincher.I currently ride 2003 Campy neutron rims. The sidewalls are ratedto a respectable 140 psi (I believe). The Tufo line has tires capableof 220 PSI, but due to design of the tire, the force on the sidewall shouldbe different than in a traditional clincher. What is your opinionof the design of the Tufo tires?Do I run the risk of blowing out a sidewall on my rims? What othertradeoffs would I be making that I have not yet foreseen?
Matt

Dear Matt,
Tufo’s clincher-tubulars do not push outward on your rims like a normalclincher, so if you put them up to bomber pressure, it will produce nosignificant added outward stress on the rim. The way the rim hook works is that it places a stiff, yet flexible “foot,” if you will, that replaces the base tape of a tubular and holds it to the rim has an inverted V-shape profile. You attach it under the rim’s bead hooks, which is very easy to do, and when you inflate the tire, it reverses the arch of the “V” and pushes the edges of the foot outward to secure them under the rim hooks. But as the air pressure gets higher and higher, it does not significantly alter the tire shape, so the outward pressure on the rim walls does not increase significantly.

I think the design and performance are great. It is a great rollingtire. A downside is that you have to bring a spare tire, rather than justa spare tube (or a spare tube and clincher). It has the advantage of atubular of losing pressure slowly when punctured, so it is safer than thesudden pressure drop that can happen with a clincher puncture. And withthe TUFO sealant, even this is a low probability.These tires do not give the weight advantage of a tubular, however.The rim is of course heavier due to the clincher’s sidewalls as opposedto the simple and strong outer surface of a tubular rim, and the extraweight of the rim-grabbing foot adds significantly to the weight of a tubular.So, you get the safety, better cornering and lower rolling resistance ofa tubular with the higher weight of a clincher. You get even easier tiremounting than a clincher, but you have to carry a bulkier, heavier itemwith you (either a spare TUFO or a spare clincher tire and tube).
Look for TUFO’snew MTB tubular clinchers, too!
Lennard