tyres

Tubeless Cyclocross Tyres - What Works?

Graeme Warren gives us his rundown on what tubeless cyclocross tyres have worked for him over the years : "The last couple of Scottish Cyclocross seasons have allowed me to run a variety of different tyres (I'm not a serial tyre swapper, but I have tried different tyres depending on what was on offer and what I had lying around).

Initially I ran a tubeless setup use Stans Crest rims - a wider rim designed for 29" mountain bike wheels, also perfectly capable of being used as a cyclocross wheel, albeit giving a slightly wider tyre profile than traditional skinny CX rims. The first tyres used were the Maxxis Raze - inflated after a bit of persusasion and stayed inflated well. The grip is low though - these are quite a quick, fast rolling tyres but struggle for grip or traction in the mud.

The following season I ran a Schwalbe Racing Ralph at each end - these inflated relatively easily and lasted relatively well - the rear eventually gave up after a year of regular use. Grip is much better than the Maxxis - a reasonable all round tyre.

For 2013 I moved to Stans Iron Cross Rims (1mm or so narrower than the Crest) and tried a Clements PDX at each end. These are slightly lighter and more supple than the Racing Ralphs, and that was reflected with the slight extra difficulty with which they inflated - I eventually succeeded with the compressor, but ran the front tyre for a year without incident once it was inflated. These have a slightly more aggressive tread than Racing Ralphs and were faultless in a relatively dry year of Scottish cross. The rear unfortunately didn't fare so well - a ripped lug in it's first race wouldn't seal, and whilst it would probably do a turn with an inner tube in or with a tyre patch, I haven't used it since.

This year, I am back on a Racing Ralph on the rear (a new design which seems perfectly grippy and inflated ridiculously easily with a track pump) and started off with a Rocket Ron upfront. Thin sidewalls on the latter led to a puncture on a rock at Strathclyde Park, which has given me the opportunity to finally try a Challenge tyre up front. Whilst Challenge are better known for their super supple tan sidewall tyres and tubulars, they now do the Grifo in a more regular tyre casing - in 60tpi or 120tpi flavours. The latter is supposedly more supple. These inflated as well as any other CX tyre I have tried, and stayed inflated without issue. I only have one race under my belt on them, but initial impressions are good - they seem to roll better on the road than the Clements PDX, but still have a good tread which kept me upright on Irvine's off camber grass. I might have a new favourite all round CX tyre here"... Graeme.

Oh heck oh no it's the Grifolo

Whilst we all love the Challenge Grifo Open Pro [the one with the skin wall] for it's grip and speed in all but the muddiest of conditions, there's one thing it cannot do, and that's run Tubeless!Although I have run them tubeless successfully for a 'while', they are not a viable Tubeless option and there are much better alternatives, including the 120tpi Grifo. The problem with the Open Pro design for Tubeless setups is that they are incredibly flexible and they can roll off the rim with some combinations of rim, tape and pressure. As such I no longer recommend the Open Pro Grifo for tubeless with any combination of rim, pressure etc. If you want to run Tubeless and want the Grifo tread then you should chose the 60tpi or 120tpi version produced by Challenge.

The 120Tpi version is now standard kit on Helen Wyman's signature bike from Kona and it's set up Tubeless from the off.

The RRP of the 120tpi is £35

Tubeless tyre pressure

Something i don't think enough people re-enforce is the correct tyre pressure to use when running tubeless.The clever blokes over at Stans quote this on the matter :

To determine a starting tubeless tyre pressure when running a ZTR rim use this simple formula: Rider Weight in pounds divided by 7 = x x - 1 = Front tyre pressure in PSI x + 2 = Rear tyre pressure in PSI

Example: 185lb rider (13 stone or 84kg) 185/7 = 26.4 Front tyre pressure: 26 - 1 = 25 PSI Rear tyre pressure: 26 + 2 = 28 PSI

Their road pressure recommendations are listed below and this is ONLY with an appropriate Road Tubeless tyre such as the Schwalbe 1:

< 60 kg / 130 lb = 5,5 bars / 80 psi

65 - 75 kg / 140 - 165 lb = 6 - 7 bars / 87 - 101 psi

> 80 kg / 185 lb = 7,5 bars - 8 bars / 108-116 psi

I would also recommend starting 10psi less than this and see how you get on (Stan says the same BTW).

For reference all Stans No Tubes rims carry a sticker stating their Max pressure, this does not apply if you put a tube in, in that case note the max pressure stated on the tyre.

If you have any query regarding pressure for other rim manufacturers then drop me a line and I'll fill you in with the necessary info.

CX Tubs, Tyres & Tubeless

Cyclocross, It's a funny/weird old game. No more so than when it comes to Rubber. For new-comers to the sport the options can be mind boggling and packed full of Jargon, for example who would know that an 'Open tubular' is not a Tubular at all but a very pliable clincher? Not I cried my good friend and ex DH MTB pro who has joined us on the start line this year (therefore depriving me of yet another point ).

To help clear up any confusion here's my round up of all things Rubbery in the world of 'Cross, CX, Cyclocross, Gravel etc...

Tubular : The pro's choice.

Tubulars or Tubs as they get called are basically a tyre and latex tube stitched together into a big sausage, this then gets attached (I'll come back to how in a minute) to a special Tubular rim. Tubular rims have a different profile from normal (Clincher) rims and cannot take normal open tyres as they have no bead socket.

The advantages are that Tubular tyres can be run at low pressures without fear of pinch flats, they give masses of grip because they can be run at 20psi, the tyre wheel combination is lighter and because of the way they are fixed to the rim the transfer of power is actually better than with normal rims.

There are disadvantages though and this is why Tubs are found mainly on Pro and 'serious' (not that serious it is 'Cross after all) riders bikes. The Tubs themselves are expensive roughly twice the cost of a clincher (read on and I'll explain). Fixing tubs for 'Cross to rims is a messy and time consuming job. If it's done correctly Tubs require a combination of glue and special adhesive fabric tape (often known as belgian tape) built up layer by layer over a period of a few days, then some poor soul has to wrestle these sticky rubbery things onto the other sticky carbon or aluminium things then tug and pull them into alignment and then put sealant in them. God forbid you make a mistake like putting the tyre on the wrong way (Sorry Steven) as the rim and the Tub are not parting company in a hurry and the mess is horrendous. [I know you can use tape only but I've seen quite a few riders carrying their bikes back to the pits when a Tub that was taped has let go of the rim] Having different tyres for different conditions means having multiple wheelsets with you, tyre choice is critical in Scotland where we can go from sand to thick mud in 24 hours, but you can run really low pressures so your intermediates can be suitable for mud, but they're still not mud tyres. They do puncture and they are not easy or cheap to repair. I for one do not like the Schwalbe Tubs as I have ripped them open so often it's not funny. On the other hand the Challenge Tubs are excellent.

In conclusion : Tubs are the Pro's choice for a reason, once you've ridden them you'll understand why, but they are not cheap and they are not home mechanic friendly unless you're significant other has no objection to the smell of solvents and glue invading the living room while you try to keep the glue warm to stop it from setting instantly during the depths of winter. Tub rims start at about £50 for Velocity Major Tom's and go upwards rapidly from there into the £000's, Tubular tyres are roughly £80+, Glueing and sticking costs £25 a wheel.

 

Clinchers : Normal tyres and tubes

You may not know it but you're probably riding clinchers already. Normal vulcanized tyres (ones that have shape when you take them off the rim), butyl rubber inner tubes and traditional rims are what most bikes will be equipped with. The advantage of this combination of tyres, tubes and rims is the endless combinations that can be put together and the cost. The disadvantage is the lack of puncture resistance, the pressure required to improve this and the weight. Pinch flats are what happens when the rim and the tube get 'pinched' together on impact with an obstacle or hard landing,  this results in a 'snake bite' puncture, so called because of the twin holes like the bite of a snake. To minimise the risk of the Pinch flat you can do 3 things:

  • Run higher pressures. This then looses you grip and makes the bike handle poorly.
  • Use super supple tyres such as the Challenge Open Pro. These are awesome tyres and do add a good amount of puncture resistance, and with a Latex tube don't weigh too much, this is a very common setup at CX races.
  • Use sealant such as Stans No Tubes inside your tubes just in case you puncture. Again this adds weight and is not fool proof as sometimes the holes in the tube will be too big for the sealant to cope with. Also you need tubes with removable cores to allow you to pump sealant in.

In conclusion: Most people will have ridden and raced on Clinchers and for the majority of people that aren't concerned about weight or grip they will be ideal due to the cost and readily available tyres, tubes and rims for all conditions. But there are better options out there in the form of Tubeless ...

Tubeless : Tyres that fit like Clinchers but as the name suggests no Tubes .

People will tell you that Tubeless is a new thing and unproven. Not True. Myself and Andy Kyffin were succesfully running Tubeless on a certain Sheffield DH'ers bikes in 2002. Tubeless involves the use of a few specialist ingredients and has many versions, for 'Cross I've used both the 'Rim Strip' method and the 'Tape' method. There is also UST - Universal System Tubless (UST) rims that require no sealant or rim strips but I've not used them for cyclocross, yet. If you take a standard clincher rim it is possible to make it Tubeless using a rubber Rim Strip, this basically seals the rim and provides an air tight seal for a standard Clincher tyre. Chuck in a bit of sealant and Bob's your Auntie. BUT I have found when using the combination of the narrow profile of most road rims ( 19mm ish ) and the wider tyres ( roughly 32mm ) that tyres do sometimes 'Burp' (leak air and sealant in corners) or even roll off the rim. This is not a problem with MTB wheels where the width of the rim and the tyres is much closer and the tyres tend to be stiffer, i've succesfully run this style of Tubeless on my Mountain bike for years with no problems.

If you invest in some Tubeless specific rims then it's a different story. Tubeless rims from the likes of Stans No Tubes, H+ Son or Velocity have a different profile and include a 'Hook' in the rim to provide more grip to the bead of the tyre to stop burping or rolling off, no need for rim strips just some light tape also means the weight saving is impressive especially when you consider the weight is saved at the outside of the rotational mass where it counts most. Combine these rims with one of the emerging Tubeless specific 'Cross tyres such as the WTB CrossWolf or the 120tpi Challenge Grifo and your good to go, almost...

The advantages of Tubeless are numerous:

Low tyre pressures so more grip, more feel and more speed. Lighter weight than Clinchers so more speed. No pinch flats so much better puncture resistance. You can use standard tyres and rims if you want so you can have tyres for every occasion and condition. The Tubeless specific tyres are half the price of tubulars and don't need messy glue to attach them. In some cases if you pick you're wheel components carefully you can go Tubeless for less money and less weight than Tubular. If you do get a puncture just bung a tube in, no problem.

There are some lessons to be learned though, it's not all a bed of roses:

Not all tyre and rim combinations work, even the Tubeless specific ones. You will get covered in sealant changing tyres if you're not careful. You might want to invest in a small compressor to seat the tyres properly, a garden spray with soapy water helps too.

In Conclusion: Tubeless is the way forward for those riders that want the grip and weight advantage of Tubulars without their cost and their technically awkward fitting, and riders that want the benefits of the ease of use and cost of Clinchers without their disadvantages; punctures, weight and lack of feel & grip. Setup can be a bit hit and miss. You don't want to be changing tyres the night before a race, but get everything done in time and the results are impressive.

 

This should go some way to helping understand the jargon and hyperbole surrounding the subject of Tyres and Wheels for 'Cross, if i've missed anything, you have any questions, or want to discuss what would suit you best then get in touch