There is a local CX race coming up that I am thinking of entering but I only have my commuting bike with max 28c tyres

http://www.chainreactioncycles.com/mobile/vitus-zenium-vr-disc-road-bike-105-2018/rp-prod159799?gs=1&sku=sku587577&pgrid=60711842818&ptaid=pla-449709552674&utm_source=google&utm_term=&utm_campaign=PLA+All+Products&utm_medium=base&utm_content=mkwid|sefFBLrlC_dm|pcrid|294922111646|pkw||pmt||prd|587577UK

Would this bike be suitable or make it a nightmare?  I was planning on just removing mudgaurds and changing tyres

It depends…..

I’m sure you can ride it, might not handle ‘as well’ as a CX bike but let’s be fair, a CX is already a compromise of speed vs comfort and stability.

Whether you can find a nobbly the frame will accept at 28mm width, and whether that’s an issue will depend on what the course and weather’s like. If it’s like it is now, you’ll probably be fine on ‘road’ tyres but if you get 2 weeks of rain between now and then, you’ll have no traction and in any case the frame will clog up with mud due to clearances.

By all means enter, but if it’s crap weather ride your MTB instead, assuming you weren’t planning to challenge for podiums (I’m assuming if you were you’d have a CX or two already anyway!!)

What race?

You might find the gearing a bit tall (course depending) but if it’s dry you’ll be ok.

hard tail mtb’s are allowed in some races if you have one?

If it’s dry you might be fine, providing you can find a vaguely off-road 28c tyre, muddy and you may face more significant clearance issues- it will still probably be fun, cx is like that.

Be OK for a summercross league but in season think it would be a bit iffy with the clearance – the bike would literally stop on a muddy course.

Mountain bike absolutely fine in local races – a better choice if you have one.

Probably fine if it’s dry and you fit mtb SPD’s not road ones, but a n MTB would probably be quicker (less chance of a puncture for a start).

what tyres? – i’m not aware of any 28c knobblies.

me neither, I think panaracer do a gravel tyre in 28c but that’s about it.

I recently stuck an old 30mm schwalbe cx Pro tyre on a build I put together for a mate. I was staggered how small it is on a 17mm rim. If you can fit in a 28 mm Road tyre then you could fit one of those unless the newer ones are wider.

I recently stuck an old 30mm schwalbe cx Pro tyre on a build I put together for a mate. I was staggered how small it is on a 17mm rim. If you can fit in a 28 mm Road tyre then you could fit one of those unless the newer ones are wider.

Not sure, I’ve got 28’s on my CX bike for road duties and the CX Pro’s whilst tiny compared to modern CX/gravel tyres are a bit bigger (but no much!)

Just measured them. On 17 mm internal rims they are 28mm, the 25mm Pro ones on my road bike (which I think have 19mm rims) are 29mm for comparison

The 35 mm cx King on the same 17mm rim measures 33 mm.

The caveat is the cx Pro I have is old.. So newer models may be larger.

Off topic, but the ops bike is a hell of a bargain for 900 quid given it has a hydrolic 105 groupset!

Pfffft, they were £800 a few weeks ago. I blame wiggle.

I managed to snag one of the SL VR ones on cycle to work when they were £800 too. Right bargain.

To the original question I’d say it would be ok, as long as it was bone dry short grass, if it’s wet or dusty it would be horrible, without even considering mud clearance. The BB is too low, the front end is too low, and the head angle is steep. My previous cx type commuter is loads more stable and I’d happily ride that off road. The Zenium is awesome on the road, but that’s where it belongs.

I might sell my old Hack if anyone wants one. Could do with new bearings in the back wheel but is otherwise dandy

As others have said, if it is dry it will be fine.  I ride all year round on 25c road tyres on gravel, grass, singletrack etc,. and the only time the tyres are a problem is when it is wet and the singletrack and grass areas have got muddy.  I still ride but it is a bit slippery and keeps your reactions in check!

You might find the gearing a bit tall (course depending) but if it’s dry you’ll be ok.

I’ve been running a compact road set – too high or too low really –  its not a deal deal breaker, give it a go, just not ideal.

Thanks for all the replies

I think I am going to order a pair of 30mm schwalbe cx Pro as seen them for a good price,

There looks to be ok clearances just now with the 28mm tyres but this might chance with lower pressures?

The race I am looking at is Irvine

I am just about to change gearing to 38t single upfront and 11 32 rear anyway so slightly lower gear than standard

The race I am looking at is Irvine

Irvine, as in the British National round this year?? Going in balls-deep there 🙂

I raced the course at the Super Quaich rnd that trialled it last year. Mud is ok for most of the course, but (and it’s a big but) there is a very long, very off camber section that got properly slick and will need some CX (rather than road sized) clearance I reckon. There is a lot more riding done at a British round so i’d expect the course to churn up far more. You’ll also have the fun of mud on your tyres potentially dragging lots of sand through your narrow frame.

Your gearing should be fine

I raced callander park on a borrowed bike last year with grass track style tyres and was all over the place, these tyres were far from slick but I spent most of my time going through the tape on the descents and not being able to get up any gradient. Though it was very muddy irvine wasn’t particularly muddy and was different type of grass but was slippery all the same and depending on what race you’re in there might have been 2days of racing on the course before you so it’ll be torn up nicely. Racing at callander park put me off a bit, was well out my comfort zone as was so all over the place and reminded me how important right kit and setup, particularly tyres, is.

bigman, is that the October version of Irvine you’re referring to?

if it takes a 28mm road tyre it won’t fit a 28mm CX tyre (if such a thing exists) as the kobbles are extra to the measured carcass width. To run a tyre that small at pressures to get any off road grip would be asking for a pinch flat too.

Then the gearing.

Then the brakes.

Then the risk of cracking a frame not built for bigger hits.

Not sure I’d bother unless it was effectively a tarmac like rock hard and silky smooth off road surface.

No the SQ one that was in February

Makes sense, the “muddy but not particularly muddy” bit threw me for a second. A or B race? I thought the off-camber was ****ed by the end of the A