Archive for April, 2009

Brett’s DT Swiss hub rebuild

Good quality hubs like the DT Swiss 240s are expensive! A good quality hub will last a long time though and can outlive many pairs of rims due to crashes etc…case in point is this pair of hubs which are being rebuilt onto their second set of rims.  The old rims were DT Swiss 4.2d’s which were getting a bit old in the tooth, plus Brett wanted to loose some weight off the wheels to keep up with Josh.

The solution?  Rebuild the 240s hubs with Stan’s ZTR 355 rims and a light combination of DT Swiss Revolution and Competition spokes.

While I had the hubs I cleaned the drive mechanism and regreased it with some ridiculously expensive DT Swiss high-pressure grease which will keep the ratchet rings in great shape for years to come.

David’s White Ind H2 hubs / KinLin XR-270 rims

I haven’t built many pairs of H2 hubs so I was really excited about this build. The White Ind H2 is an American made hubset which focuses on durability with a titanium freehub body and “real-sized” bearings. At 93g / 248g this makes the hubs heavier than, say, the DT Swiss 240s but still lighter than Shimano DuraAce. These hubs are very popular in the USA but surprisingly rare here in NZ.

The goal for this build was a durable pair of everyday clincher wheels so we selected the KinLin XR-270 rim and a sensible 28h front, 32h rear spoke combo.

To reduce the weight and add improve aerodynamics the spokes are bladed Sapim CX-Rays with Sapim spoke nipples.

Total wheelset weigh is a very respectable 1513 grams.

Marco’s weight-weenie disc front wheel

The Tune Princess front hub is a seriously light disc hub: The hub shell and axle are aluminium and each flange has a wrap of carbon around it’s circumference to help deal with the forces created by the tensioned spokes. Both sides of the shell are heavily machined and the hub weighs a feathery 107grams!

Laced to this light hub is a Stan’s ZTR Race rim. The Race is claimed at 284g but all of the examples I’ve built have come in between 293g and 297g – it’s not like Stan’s products to be over their claimed weight but this is still exceptionally light for such a stiff rim. The ZTR Race is a proper ‘race’ rim: There is a rider weight limit, no warranty, and special building instructions but despite this the other pairs which I have built are running well after enduring some serious punishment.

Holding it all together are Sapim CX-Ray spokes and matching SILS nipples. ‘SILS’ is an acronym for “Sapim Integrated Locking System” – basically the nipples have a mechanical lock to stop them unwinding with use which is great with lower-tension wheels like this ZTR Race rim. The mechanical lock serves a similar purpose to a chemical lock like the DT Swiss Prolock nipples or SpokeFreeze but is easier to work with and the lock is not broken if the nipple ever needs to be turned for truing.

Total wheel weight is an amazing 554 grams bare, or 567 grams with the tubeless tape and valvecore fitted.

Tubeless Road Tyres

A topic which has gained a little momentum lately is tubeless road tyres: Airtight tyres which do not need an innertube. The claimed benefits are lower rolling resistance, better grip, a decrease in punctures, and a smoother ride due to running lower tyre pressure. I’ve been riding a pair of Hutchinson Fusion2 tubeless tyres for a few months now and wanted to share my experiences. I love tubeless: my mountain bike, cyclocross bike and now one of my road wheelsets are all running tubeless.

A bit of background on road tubeless is below if you’re interested.

For these wheels I used standard non-tubeless Kinlin XR-270 rims and two layers of Stan’s airtight tape (as per the Stan’s instructions) to seal the rim. The Huchinson Fusion2 tyres mounted well, inflated with a floorpump, and would hold air without any sealant. Since these wheels will be primarily used for rainy-day riding and commuting I added 1/2 cup of Stan’s sealant to each tyre to seal any cuts while riding.

By removing two worn Continental GP4000s tyres, Ritchey rimstrips and Specialized 44mm Lightweight tubes and adding the Fusion2 tyres, Stan’s tape and a cup of sealant I added 4 gram to my wheelset.

The ride: Smooooth. I run normal tyres like the GP4000s at 95-105psi for my 74kg, and with the tubeless tyres I run 85-95psi which gives an amazingly smooth ride. The rolling resistance doesn’t feel like it changes between 85psi and 110psi with these tyres so I see no reason not to run them low. The tyres don’t feel as fast as other clinchers, in fact no matter what pressure I run them I find them a bit ‘heavy’, so I don’t think they’re ready to be used as race tyres. The cornering grip however is fantastic: The lower pressure means these tyres really hook up and the bike turns-in quicker. Fitted to my rain bike they’re perfect – smooth enough to take the edge off, plenty of grip on wet descents, and the risk of puncturing is much lower.

As you can see from the photos there are some cuts which would have resulted in punctures on a normal tyre. If you do puncture you can easily fit a standard innertube and continue riding.

I’m sure as the tyres evolve they’ll get better and feel faster, however for now I’d suggest only using the Fusion2’s for non-competitive use.

What you’ll need to go tubeless:

I’ve tried the Stan’s method on both the XR-270 and XR-300 rims. To convert these rims you’ll need a roll of Stan’s 21mm Yellow tape, two 44mm road valve stems, a pair of Fusion2 tyres, and I’d recommend some sealant. Contact me for costs. The conversion is quite easy to perform yourself following the Stan’s instructions or you can return your wheels to me and I’ll fit the tyres.

Road tubeless background:

The concept is very similar to tubeless mountain bike tyres however due to the higher pressures involved the risks (and consequences) of failure are higher.

There are currently a limited selection of wheels and tyres which are “Tubeless Ready” however for 2009 this range looks to be expanding. Currently Shimano, Fulcrum / Campagnolo, and Corima make tubeless wheelsets and Hutchinson is the sole manufacturer of tubeless tyres.

There are two parts to the tubeless system: The rim and the tyre (duh!) and both need to be airtight.

The most important aspect of a tubeless road tyre is the bead: The bead needs to be very strong ensure that it’s diameter stays constant over time (most tyres stretch with use) and very stiff to ensure that it’s difficult to accidentally force the bead from the rim (called ‘burping’ due to the rush of air which escapes.)

The casing and tread of the tyre need to be airtight and so the inside of the tyre has a special coating.

Most rims have holes drilled through the inner wall to insert the spoke nipple. In most cases these are covered by a cloth or plastic rimstrip to prevent the holes from puncturing the innertube. For a tubeless system these holes are either eliminated by having the nipples enter from the inner side of the rim by using fancy nipple carriers (ala Mavic UST) or inserting the nipples through the valvehole and using magnets to track them into place (ala Campagnolo / Fulcrum.)

In the mountainbike world Stan’s revolutionised the wheel by first offering sealing kits to convert normal rims to tubeless, and then by launching rims specifically designed for tubeless. Stan’s use an very strong airtight tape to seal the spoke holes – this system works very well and is light weight and simple. Applying this tape for road use works well and in the 8 months of use I have not had any problems with the system.

David’s Hope Pro2 / Mavic XM819 wheels

Red Hope Pro2 hubs with a 20mm front axle laced to the fantastic Mavic XM819 rims.  The XM819 used to be billed as an XC rim but at 520grams it’s too porky for this purpose – luckily it’s super stiff and very durable so it works well on all-mountain or freeride bikes and is UST-compatible.

Red spoke nipples were used to add some colour.  The XM819 rims need longer than usual nipples to make sure that the nipple doesn’t get lost if a spoke is removed…luckily I had a bag of 14mm Sapim nipples which fit the bill perfectly.

Scott’s Giant Anthem X

At first glance this looks like a pretty standard Anthem X1…take a closer look and you’ll notice the white F32 fork, full XT drivetrain, and white ODI grips and Selle Italia saddle.

Ian’s Yeti 575

The week before this year’s Karapoti Ian’s Specialized Epic frame developed a crack.  Ian had purchased this 575 frame ready for a long-travel build but with just two days to spare I swapped his Epic’s XTR build kit and Wheelworks wheels onto the new frame.  Ian had never ridden a long travel bike before and he only had one chance to ride the bike prior to race day.  Showing his class he won his age group.

Josh’s Chris King rebuild

These hubs were originally laced to a pair of DT Swiss 4.2D rims.  The original build quality was poor and the rear wheel would constantly go out of true: Josh contacted me to solve this so I relieved all the spoke tension from the wheel then re-tensioned and trued.  This solved the problem and the wheel gave about 18 months of service until Josh decided to drop a bit of weight and eliminate the DT Swiss tubeless strip by moving to the Stan’s ZTR Arch rims and lighter spokes.

I rebuilt the hubs using DT Swiss Revolution spokes and alloy nipples for the front and non-driveisde rear, and stiffer DT Swiss Competition spokes and brass nipples for the driveside rear.

Sorry for the photo quality – luckily my wheelbuilding skills are better than my photography talents :-)

Torx fittings – a word of warning

Torx fittings are becoming more and more common on bike components. FSA was one of the first companies to use this style of fastener and now SRAM / Truvativ, Campagnolo and Shimano have jumped on the bandwagon. It started with a few rotor bolts, now most chainring bolts are Torx, shifters are being held to handlebars with them, and bleedvalves use them.

Personally I don’t see the point: Allen head fasteners work just-fine, we’ve all got multi-tools with 4mm, 5mm and 6mm allen keys, and lugging around a T25, T27 and T30 as well doesn’t make much sense. There are upsides to Torx fittings: Both tool- and fastener-life is increased.

Putting that aside there is one caution when using Torx fittings – make sure you have the correct size tool! With allen head fasteners it’s quite clear that a 4mm allen key will not turn a 5mm head but with Torx it’s not so clear: a T27 will fit quite securely into a T30 but problems will only occur once a bit of torque is applied and the head of the fastener deforms.

To illustrate this I set up a bit of an experiment: An old FSA T30 chainring bolt, a T27 socket, and a torque wrench.

First lets take a look at how securely the different size sockets sit in the chainring bolt:

T25 - clearly a loose fit in the chainring bolt

T25 - clearly a loose fit in the chainring bolt

First the T25 socket: This slides into the T30 chainring bolt but is quite clearly not the correct size.

T27 - The wrong size but it feels like a good fit

T27 - The wrong size but it feels like a good fit

Second the T27 socket: This is where the problem lies. The T27 fits snugly into the chainring bolt but is not the correct size and attempting to apply torque to the chainring bolt will deform and destroy the chainring bolt.

T30 - The correct size

T30 - The correct size

Third the T30: This is the correct size socket for the chainring bolt.
If you’re not sure what size Torx fitting you’re attempting to work on my suggestion is to start with a larger socket and work downwards in sizes until you find the correct size. This will eliminate the risk of selecting the wrong size socket and destroying the fastener.

Out of courosity I applied torque with the T27 bolt to see what the failure point would be – at around 20Nm the chainring bolt deformed. This is more torque than should be used to tighten a chainring bolt but much more torque than this might need to be applied to loosen a stuck bolt.

Chainring bolt failure at 20Nm

Chainring bolt failure at 20Nm

Ben’s DT Swiss / Ambrosio training wheels

This was an awesome “new classic” build – 32 hole box-section Ambrosio Excellight rim laced to DT 240s hubs with a combination of DT Swiss spokes.

For the rear wheel where lateral stiffness is important I used DT Swiss Competition spokes which are 2.0mm at the head and thread and 1.8mm in the center section. These spokes are laced 3x both sides and held in place with black brass nipples.

On the front wheel the hub’s flange spacing is much wider (because of the lack of cassette) which inherently builds a stiffer wheel – to reduce this stiffness and increase ride ‘feel’ plus loose a bit of weight I used DT Swiss Revolution spokes which are also 2.0mm at the head and thread but only 1.5mm in the center section. Again brass nipples were used on the front wheel – these are training wheels so the brass adds a bit of long-term security – and the spokes were laced 3x for the classic look.

Ambrosio rims are getting quite hard to find, especially here in NZ, and Ben was lucky enough to have had these in the back of his cupboard for a few years. They built up really well and should give many years of reliable service.

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