In Issue #116 of Singletrack Magazine, David and the crew tested six sets of sub-£1500 carbon mountain bike wheels. We subjected all of these wheels to the same bikes, the same tyres, same air pressures, riders, trails, weather conditions and abuse, all the while keeping and comparing notes.
We then settled on three category winners: Easiest To Live With, Most Comfortable, and Best Value. In selecting the easiest wheels to live with, the main factors we’ve considered are serviceability, warranty support, and lack of proprietary or obscure standards. The most comfortable wheelset was selected by assessing ride quality in back-to-back comparative testing. Best value was selected on the basis of not just price, but ride quality, set-up, durability and servicing set against that.
Winner Best Value: Bontrager Line Pro 30 Wheels
In Bontrager’s growing range of mountain bike wheels, the Line series aims to cover the trail riding and enduro racing categories. Featuring wider and burlier rims than the Kovee wheelsets, the Line series wheels are designed to be fitted with chunky tyres and strapped onto longer travel bikes. They’re a bit heavier overall than an XC racing wheelset, but they are made for a’beating.
Bontrager currently offers several Line wheelsets, including alloy and carbon options. The Line Pro 30 wheels we’ve got on test here utilise carbon fibre rims (that’s what the ‘Pro’ part of the name means), and they feature a 29mm internal rim width (which is probably close enough to ’30’ for Bontrager’s marketing team), and they’re available in 27.5in and 29in diameters.
Bontrager Line Pro 30 Carbon Wheel Features
- Available in 27.5in and 29in diameters
- OCLV carbon fibre rims
- Tubeless Ready (TLR) rim design
- Internal rim width: 29mm
- Designed for 2.3in – 2.6in wide tyres
- CNC machined Rapid Drive alloy hubs
- Boost hub spacing only
- 6-pawl Rapid Drive freehub mechanism w/108 points of engagement
- Shimano & SRAM XD freehub bodies available
- DT Swiss Aerolite straight-pull bladed spokes & Alpina alloy locking nipples
- 28 x spokes front and rear w/Stacked Lacing pattern
- Includes TLR tubeless rim strips and TLR tubeless valves
- Actual weight: 1658g (27.5in wheels tested)
- RRP: £899
Bontrager’s Line Pro 30 Carbon wheels are among the lightest in this grouptest, yet also some of the cheapest. That can partly be explained by the fact Bontrager is owned by Trek, and as such gets to exploit massive economies of scale. This also means that the wheels are full of stuff that Bontrager and Trek have developed and patented themselves, though of course with the same engineering goals of other companies.
Most carbon fibre parts are made in roughly the same way: sheets of woven fibre are cut, laid up, then shaped with various moulds and mandrels as resin cures around them. Particular methods might be unique and patentable, but there are many precise routes to plastic parts with very high tensile strength in multiple directions.
Everyone manufacturing in carbon wants to prevent voids (air gaps) inside the layup, which act as weak points where cracks and delamination can start. Trek’s process used on these wheels is acronymized OCLV, which stands for ‘Optimum Compaction Low Void’.
As well as their own process, Bontrager also builds these with its own hubs, boasting 108 points of engagement (that’s 3.3°, which translates to quick pickup of pedal input). The freehub is also fairly quiet in use, if that kind of thing bothers you. One thing I did notice was that until the wheel had been clamped into the back end of a bike a few times with no cassette on, the freehub endcap would fall out if I looked at it funny. It was also quite large, so not every cassette tool I had could fit over it.
On the rim bed you’ll find Bontrager’s own rim strip, pre-fitted along with tubeless valves. Should you ever have to replace a spoke, it’s nice to know the strip will just pop out and back in rather than having the hassle of peeling and retaping. In terms of tubeless, the front tyre went on easily enough though the rear was difficult. I handed it to Chipps, who can normally do any tyre with just his hands, but even he needed three (three!) levers to get the last bits of bead over the lip. Even with soap, the back also had some trouble seating beads. To get the last two snapped into place, I had to inflate, gingerly set the wheel down then stand on the tyre, hoping the whole time it didn’t pop and plaster my crotch with latex (time and a place, you know?).
Once on, the wheels were entirely free of issues for the whole test. In use, they were stiff and responsive. Front and back both have 28 spokes, which was a surprise; they were stiff enough that I’d have sworn they were 32s. Those DT Swiss Aerolite spokes are of the straight-pull variety, so it’ll be worth getting some spares from a Trek dealer to keep on hand if you break any. We didn’t break any.
Out of all the wheels on test, I’d say these are good all-rounders. By that, I really don’t mean to damn them with faint praise; they genuinely have well balanced characteristics that mean you’ll be able to use them consistently for a lot of different types of riding. We tried them on everything from trail centres and smooth moorland singletrack, to rocky Hebden tech-fests. They never felt out of place.
The only thing that made us slightly nervous is that these had the only rims on test with bead hooks. The sidewall material on such rims is thinner where it meets the rim bed, which can create a weak point under impact forces (hookless beads make for stronger rims by eliminating that thinner sidewall section). Despite plenty of rim strikes though, these wheels showed no signs of damage by the end of testing.
With a weight of 1,658g (1540g claimed) there are slightly lighter wheelsets in this test, but not by much. Considering their price, the low weight of these Bontragers is quite astonishing. Trek also states these wheels have no rider weight limit, so if you’re on the heavier side and looking for something with the warranty backup of a large company, these are worth considering.
These may not have the best feel of all the wheels on test, and very light riders might find them a bit stiff, but they’re well built. In terms of price per gram saved nothing else holds a candle to them and, as such, these win the best value category hands down.
|Line Pro 30 27.5 Boost
|Trek Bikes, trekbikes.com
|by David Hayward for 5 weeks