For CYCLO CROSS RACERS, tyre choice and tyre pressure are some of the most wrangled over decisions on race day, but when looking to upgrade your current set up, how do you decide which way to go?
In this article we’ll explain the advantages and disadvantages of the main options and make some recommendations to help you avoid the pitfalls.
What are the options?
Bicycle wheels have three main rim / tyre interface options; Clincher, Tubeless and Tubular.
Clincher tyres use an inner tube to retain the tyre pressure and the tyre is held onto the rim with the tyre bead and rim hook.
Tubeless rims/tyres look similar to clincher but are designed to work without an inner tube, the tubeless tyre bead locks onto a specially designed rim hook, tyre sealant is added to make the tyre airtight.
Tubeless / clincher rim
Tubular tyres do not use a bead or hook and glue directly onto a tubular rim with adhesive or special double-sided tape (don’t use tape for CX – low pressure and the lateral forces massively increase the risk of rolling the tyre off the rim).
What are the advantages?
- Quick and easy to change tyres
- A variety of tread options and some supple tyres available
- No special rims needed
- Tyres are generally easy to fit/remove/repair
- Most rims can be used for training with road tyres
- Lowest cost
- Self-sealing punctures for small holes/cuts
- Improved grip if reliable low tyre pressure can be achieved
- Does not suffer from pinch punctures
- Quicker to change tyres than tubular
- You can use an inner tube & open tubular tyre if you don't get on with tubeless
- Medium cost
- Hugely improved grip
- A huge variety of tread options and some very supple tyres available
- Lightest rims available and are less susceptible to damage
- Can be used with very low tyre pressure
- Less susceptible to pinch punctures than tubed clinchers
- Inner tube is encapsulated, cushioned and protected by the tyre
- Can be ridden to the pits flat (but you’ll probably trash your rim/tyre)
- Will not burp
What are the disadvantages?
- Susceptible to pinch punctures
- Few light weight and strong options
- Old rims designs often have a very narrow internal width
- No industry standard makes rim/tyre compatibility trial and error
- When a poor fit, tyre burps lose air pressure
- Can be very difficult to fit/remove
- Last minute tyre changes are tricky and messy
- Limited (but improving) tyre choice
- Tyre sidewalls are reinforced making them ride hard
- Many rims are too wide for UCI races, if your rims are +20mm wide you'll be restricted to a 31mm tyre, a wide rim increases a tyre's measured width
- There is huge variation in tyre sizing between brands
- Expensive carbon rims are not particularly light
- The lightest rims cannot be used with road tyres
- Carbon rims are susceptible to damage with punctured/burped tyres
- Gluing tyres is a process not an event
- Very difficult to repair a puncture if sealant doesn’t seal
- Last minute tyre changes are impossible
- Having tyre options requires multiple wheel sets
- Some tyre brands are fragile and require careful cleaning and storage
- You need to keep an eye on the condition of the glue to prevent rolling tyres in races
- You can only use tubular tyres
- A potentially expensive option
Now I’m just confused – which is right for me…?
Whilst there is no industry standard for tubeless rims and tyres, and until products are updated to whatever the standard is when announced, we will not recommend tubeless tyres for cross racing.
One brand's tyres might work well with a particular rim, another may not. The trial and error involved is hugely frustrating and usually ends up limiting tyre tread choice or with running to the pits.
(Update; some tyre manufacturers are making announcements of new road tyres produced to ETRTO Road Tubeless Standards, however the standard is yet to be confirmed.)
Tubular is the way to go for cross racing, the improvement in grip and weight savings available make it the go to option.
But, if you need the flexibility of being able to change tyres quickly, or are limited to one wheel set, then we recommend the use of the LOWMASS Aluminium Tubeless Wheelset with Challenge Open Tubular tyres with Dugast latex inner tubes.
This combination is as good as clinchers get, particularly with a reasonably wide internal width rim, (although in our back to back tests Tubulars offer significantly more grip than Open Tubulars) and you'll have access to the same tyre treads used to win CX World Championships.
We have ridden 1000’s of miles on latex tubes; pinch punctures and thorn punctures are hugely reduced compared to a butyl tube, and you can ride at near tubular tyre pressure (I’m 75kg and ride on a 20mm internal width rim at 22 psi).
Challenge's Baby Limus is a magic bullet of a tyre, in Tubular or Open Tubular form, it rides like an intermediate in dryer conditions, and you'll have confident grip until conditions turn into a deep mud fest. If you buy one tyre for cross - make it the Baby Limus!
Challenge Baby Limus
We would like to be able to offer our recommended tyre for sale, but the crazy market forces that drive the cycling industry mean that you can buy them with free postage for only £2.20 more than we can!
This has happened because the Challenge distributor changed recently and the old distributor flooded the market with cheap stock. Our advice is grab a cheap one whilst they are available and we will stock them in the future.
Other recommended tubular tyres:
Dugast’s Small Bird is a brilliant dry and summer tyre, supple and fast, it provides more grip than looks like it should. Dugast tyres are especially supple but this makes them somewhat delicate and they need careful cleaning, drying and storage. To extend their life, painting Aquasure along the edge of the base tape (not the whole sidewall) strengthens this weak point.
Dugast Small Bird
FMB’s Super Mud is our favourite mud tyre, also supple, it bites better than anything else we’ve used. It’s less delicate than Dugast and bites better than the Challenge Limus.
FMB Super Mud
However, Challenge Limus’s tread is more self-supporting than the Super Mud, in conditions where it’s mud over a firmer base, the Limus has a slight advantage over the Super Mud.
Training on tubs? There is a lot of sense in training on the same tyres that you'll be racing on, but we restrict this to skills sessions otherwise it can get a bit expensive... We use Tufo Primus for regular training, it offers a step up in grip for rooty Sven hill reps, with sealant in they are very robust and are cheap to replace.
When it gets really muddy though, we go to Challenge Limus Open Tubular with Latex tubes.
Our view on Tubeless:
There is a place for tubeless – Mountain Bikes and Road Bikes
Today’s mountain bikes have wider rims and high-volume tyres, additionally the extra years of development mean that tubeless works.
The higher tyre pressures used on road bikes makes a big difference, current tyres offer a lower rolling resistance than tubular so are a compelling option.
Cyclo cross is a low volume, low tyre pressure application, and current offerings are simply not reliable.
If you're planning to race UCI races (think National Trophy or National Championships), you will be severely limited by tyre choice. A 31mm Vittoria Terreno Mix tyre just fits in the commissaire's tyre width gauge on a 23mm internal width rim, and a 33mm Challenge Limus TLR is too wide on a 20mm internal width rim. Again, tubular is the way to go for UCI races!
We have commissioned a UCI tyre width gauge (they are very hard to get hold of!) to test and collate a resource of tyres and wheel combinations which will pass the UCI test - watch this space.
No carbon tubeless in the LOWMASS wheel range, why?
Aerodynamics plays a large part in the advantages of carbon tubeless rims for road, but given that low rim weight is a greater advantage for cross, the huge additional cost for carbon tubeless rims outweighs any small aerodynamic performance improvement at cross racing speeds.
We believe that for cross, it's better to spend money on tubular wheels, than carbon tubeless.
For those who decide to choose tubeless, there are lightweight aluminium tubeless rims available with a very similar weight to many carbon tubeless rims, and when damaged (imagine what happens to a tubeless rim when you need to brake with a flat tyre) will cost less to repair too.
The LOWMASS Aluminium Tubular wheelset was developed to make tubular a more accessible option. Its weight and tyre performance per £ make it a significant upgrade compared to carbon tubeless.
Many cyclo cross racers look to capitalise on the best choice of tyres, available grip and reliable low tyre pressures, by owning multiple sets of tubular wheels. Each having tyres glued to suit the conditions expected at the time/venue. In this case it is really important to have matching hubs and discs to make last minute tyre/wheel changes quick and easy.
If owning several pairs of tubular wheels is not an option, for close to the price of a carbon tubeless wheelset, you could use our LOWMASS Aluminuim Tubeless wheelset (the same rim weight as ENVE 3.4 disc tubeless rims) with Baby Limus Open Tubulars and Dugast latex inner tubes for 2/3rds of the season, then switch to our LOWMASS Aluminium Tubular wheelset with mud tubulars and enjoy the benefits of tubular when it really is an advantage...
Tubular sounds like too much hassle for me!
Gluing tubulars requires a bit of patience and a bit of space.
It’s as simple as - making sure the rim and tyre are clean, brush on a layer of glue (takes about 15 mins), leaving it to dry for 24 hours and repeat, build up 3 thin layers for the rim and 2 on the tyre. One more layer on each and put the tyre on. Leave for 24 hours and then you can ride.
Once glued, you need to keep an eye on the condition of the glue, if the tyre is coming away from the rim, pull it off, clean up with acetone and re-do the final stage above.
It isn’t as tricky as most people think and if you are serious about racing, it’s well worth the investment in time.
The process is very well described in THE CYCLOCROSS BIBLE (Cyclocross' best coaching manual) and is a must read if you are new to tubular tyres or want to improve your cornering grip.
Tyre pressure needs its own article…
It is worth noting that manufacturer's minimum tyre pressure for cyclo cross tubeless tyres are very high; Challenge is 45psi, Vittoria is 35psi & Schwalbe is 40psi.
These minimums have probably been set high to prevent the burping problems so many people seem to be experiencing, but are significantly higher than the 20-30psi range which provides the benefits of good grip for cross.
For comparison, a Challenge Tubular's minimum tyre pressure is 23psi and is 30psi for an Open Tubular.
Keep an eye out for a future blog on tyre pressure, and another on making you bike into a race machine on a budget too.
In the mean time, the Wyman method devised by Helen Wyman is a good starting point for dialing in your tyre pressure;
Tubular tyre psi = (your weight in lbs / 10) + 5
Clincher tyre psi = (your weight in lbs / 10) + 10
Once you're set up with your chosen wheel/tyre system, it's time to go out and play with tyre pressure. ACCU-GAGE tyre pressure gauges are highly recommended and make dialling in your tyre pressure easy.
We have deliberately avoided discussing rim brake vs disc rims in this article. It is suffice to say that rim brake rims are either light but will wear out quickly or not lightweight…
Lastly, remember that if you chose to ride at below your wheel and/or tyre manufacturer's minimum tyre pressures to achieve optimum grip, you may invalidate your manufacturer's warranty.