JeffOYB

Curious...

Stonerider1

Wider is faster on most rough, bumpy courses as long as the weight penalty isn't too great. Wider tires offer a bigger contact patch and you can normally ride lower pressures.

Spoonrobot 

They are faster but no one's arguing that. They're banned because cyclo cross is skinny tires and drop bars and the UCI has an interest in preserving this status quo.

Same reason road racing banned aero bars in mass starts and track racing is fixed wheel only.

Stonerider1

The good news is that you can run wider tires in the USA unless you are racing Pro in a UCI race. For amateur racers in 99% of the races they don't enforce the tire width. I've seen plenty of guys race a MTB. On an extremely rough course last year, I ran a 1.8 Renegade on the front of my TCX Advanced frameset and beat a bunch of guys that normally place ahead of me in a 40+ Masters race.

50voltphantom

Personally, I completely support the UCI rules regarding tire width and handlebars. Without them, what you have is a tame MTB course being ridden by, effectively, 29er mountain bikes. Cyclocross is riding road bikes offroad. Riding 'skinny' tires isn't necessarily fashion, or ego (<28mm CX tires were once common); It's about playing the sport with a regulation-sized "ball". If you changed the dimension of a football or basketball, you'd have a different game on your hands. No different than softball vs. baseball.

fietsbob

Yup, UCI.. .. Local, Non UCI or US Cycling, sanctioned races, You can use Your MTB.





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Stonerider1

I ran 700x40 Maxxis Ramblers tubeless on my Giant TCX in a training race Thursday and finished 3rd out of 19 racers. The extra volume certainly helped smooth out the bumpy course.

1speedlos

Gotta disagree on your examples. Both aerobar bans in mass starts and fixed wheels on the track have nothing to do with the status quo. They are simply about safety. If you've raced on the track, imagine some bonehead coasting in the middle of a pack! Or if you've been on a group ride with a noob on aerobars...

Los

redlude97

have you seen roadies using IABs? Its no different if not more dangerous. I don't think it is about safety at all.

1speedlos

I'm sorry, what are IABs?
I haven't raced on the road in about 15 years, so I'm not super up-to-date on current rules, but I've been a bike mechanic for about 25 years. For a long time, the UCI clearly stated its position on equipment that was purely designed for aerodynamics was about safety- a rider on aero bars in a mass start event does not have the control necessary to safely ride in those conditions. I'll bet we both know riders who are sketchy regardless of equipment...

Sure, rules such as tire width might be arbitrary, even anachronistic, but they might figure that some lines need to be drawn. As far as whether that ruling is to maintain a certain aesthetic, or out of nostalgia, I wouldn't venture a guess.

Los

Jakedatc

IAB- Invisible aero bars... basically rider skill/balance getting around the non aero bar rule. I'd think the original rule is because there are no brake levers on aero bars.. plus it's a projection that isn't too safe in a group crash. IAB.. still no brakes but no extra stabby parts.

grolby

This question is easily answered with 5 minutes of research, but why do research when you can make up speculative (and wrong) answers out of whole cloth?

The UCI was pretty clear on its reasoning in handing down the 33mm tire width limit, and it wasn't speed and it wasn't about preserving the skinny tire status quo. With respect to the former, a speed difference is irrelevant if everyone has equal access, with respect to the latter, the previous 35mm limit had already codified cyclocross as a skinny-tire sport.

From a CX Magazine article published at the time:
Whether this rule has the intended effect was contested at the time, and is still extremely questionable. But that's the reasoning.

Finding that article took me three minutes of Googling and clicking on links. I happen to remember the hubbub and reading these articles for the first time six years ago, but seriously. Come on, people.

Oh, and the ban on aero bars in mass-start racing isn't about purity. Riding on aero bars in a group is dangerous as hell, and introducing protruding elements from handlebars increases the risk they could snag on something, as well as posing additional hazards in a crash. Same deal with fixed gears in track racing. There are important safety reasons to maintain consistency in equipment in the extremely tight quarters of velodrome racing.

Spoonrobot 

no more posting until googling has been exhausted.

coominya

That's a good point, a logical point. We need rules in society and in sport, if the rules are not liked then the democratic process will change them in due time, in the meanwhile people can always take their oversized baseball bat to a back ally and play their own game.

I came to this thread from a "useless" search about aero bars for my hybrid toughroad so I'm no cyclocross purist that's for sure

Feaduin

The answer is that in some specific cases 35mm + tires are faster while in other situations a narrower tire was thought to be advantageous. The result was that riders wishing to compete at high levels needed to mount multiple tire widths on multiple sets of rims (if you are racing at the elite level you are also using tubulars so no quick tire changes). The UCI implemented the 33mm rule hoping to level the playing field by reducing the number of tire and rim combos elite riders needed to purchase and transport to races.

Whether or not the 33mm rule has been successful in creating a more level playing field is a subject that is still up for debate. However, if you are not an elite racer and do not plan on competing for a national championship you really do not need to worry about this rule. Almost all cross tubular tires come in 33mm width but some manufacturers have begun to release 35mm clinchers (Ritchey for one) for use in amateur races.

JeffOYB

I'm also wondering (in another thread) about how many racers today use 30's?

...Much less 28's. Are 28's still around?

I'm guessing only tiny riders use 30's. Or maybe elites keep a set around for the rare all-soft all-muddy course. ?

idc

My pit bike has a rear 30mm Schwalbe because that's about all that will fit (not a proper CX bike). Otherwise I run PDXs or MXPs which end up measuring around 34-35mm on my rims. Good enough for just about any course I see around here.

I could fit larger tires which might help on some courses but with the weight penalty and hassle of extra tire/wheel choices I'm not sure it would be faster on average - so I think having a UCI limit may actually make sense in terms of indirectly reducing equipment since tire manufacturers probably won't make CX tires much bigger than 35s.