skinnyguy

just wondering if anyone here actually races on a 21mm wide tire is is the consensus to ride a 23-25mm tire? 21mm would be more aero with rims and from what I have read the aero gain with a 21mm more than offsets any rolling resistance loss it may have compared to a 23mm.

Creakyknees

When I bought my 404's they came with some 21 tubies already glued so I raced a few races on those. Scared the crap out me, purely and entirely in my head mind you, because I was used to 25's (my training clinchers) and the skinnier tires just felt different in the turns. I eventually sorta got used to it, and the wheels / tires were definitely fast. But when I eventually flatted, I replaced with 23's.

carpediemracing 

I ran 22s on my HED Stingers and then 23s. When I had the 23s I flatted at a race and borrowed back a wheel I sort of "permanently loaned" a teammate, equipped with 21 mm tires. I raced those wheels for 5 solid years so I know them well. I even glued the tires on for my teammate.

Well when I swapped I couldn't tell the difference, at least in cornering. The 21mm equipped wheel felt slower but I can't say what caused it - the profile (narrow 46 mm vs toroidal 60 mm), weight (my Stingers are lighter), or the tires.

grolby

There's a short bit in Laurent Fignon's biography where he talks about his team, sometime in the 80's, being one of the first to use 23mm tires (19-20mm tires were the standard at that time). It was hard to get the riders to accept them, but then they went down a descent in the rain and the guys on the bigger tires left everyone else behind.

So, the expansion in tire size had a dramatic effect. The idea of racing a crit on 20 or 21mm tires is scary. Regarding aerodynamics, with wider rims now becoming the standard, there's probably no advantage to going narrower on those rims; on non-aero rims, I wouldn't sweat the difference. Narrower tires have stuck around in TT use, but again, on the new generation of aero rims they are probably not worth much.

I would suggest not going narrower than 23mm.

tetonrider

narrower is faster when you have zero yaw, which is, outdoors, basically...never. even still the difference at low yaw between a 21 & 23 is very, very low.

a big reason why pro teams have gone to wider tires is to avoid pinch flats with the fatter rims. the rolling resistance was a side benefit.

carpediemracing 

I rode 22s (which were labeled 21 mm until recently) until 2009 without problems and I only do crits and I prefer the ones with super hard turns that require good cornering technique. 17 or 18 mm tires, okay, that's narrow, trying to balance pressure with resilience is tough/impossible - the rear would chatter no matter what I did. I ran those on 17 mm wide rims. 20 mm on a standard 20 mm tubular rim, a bit narrow but it was also a lower quality casing, but because of durability I raced those tires a lot (Panaracer nylon casing 200g tire). A good quality 21 mm tire is fine, given proper technique and normal 20 mm wide rims.

With the wider rims like HEDs etc the wider tires are good if only to protect the rim from the pavement when really laid over.

skinnyguy

i was referencing the velonews article found here on tire width:


Tire size Just as subtle changes in the shape of each
rim’s spoke bed proved vital to both overall
aerodynamics and crosswind performance,
tire selection can have a dramatic impact on
the same. Vittoria provided us with 21, 23
and 25mm Corsa CX tires to help us find
the best combination for each wheel. Rim
and tire are a system, and one impacts the
other. In fact, we saw changes of as much
as 97 grams of drag, or nearly 10 watts at
30mph, with the same wheel simply by
swapping from a 21 to 25mm tire.
On average, a 21mm was the fastest option
for all the wheels tested. But the impact
of tire size was not consistent across
all of them. On the Psimets, for example,
tire size had very little effect — less than
10 grams difference at most yaw angles. On
the Bontragers, a 21mm tire saw a sharp
drop down to 953 grams of drag at -10° yaw,
while a 25mm tire saw a sharp spike up
to 1050 grams. In other words, the wheels
were stalling out at -10° with a 25mm tire,
but not with a 21mm tire. The 23mm tire
was right in the middle.
Of course, numerous other factors need
to be taken into account regarding tire selection.
The rolling resistance associated
with a 25mm tire will usually be lower than
that of a 21mm, and both 23mm and 25mm
will corner and handle much better than
their skinny sibling. Racing a technical criterium
on a 21mm tire for the sake of a few
grams of drag isn’t a great idea, but throwing
21mm tires on for a time trial will likely
save a few seconds. As with most equipment
selection, there is no right answer for
every situation.

It is funny how people mention about the wider rims needing wider tires but if you read that paragraph you can see just how much the Bontrager (27mm wide) were affected by using 25mm tires vs the 21mm tires. Crosswind performance was also better. Even in real world conditions @ 40km/h that 100g of drag would still save you around 7w of power. Marginal I know but a 21mm tire would only increase your RR a few watts at best so you still end up with a 5w gain. I only do RR so crits are not an issue for me.

merlinextraligh

Presumably your road races still have turns and descents.

When were young and stupid, we used to race on 19mm tires.

Walrus

I used a pair of Maxxis Xenith Hors Categorie tires for a while last year that were 20mm.

They were on clearance, presumably because no one uses them, so I decided to give it a try.
At first I noticed the bike felt a bit more lively, but after a while I started disliking them.
The ride felt rougher and my confidence in corners just wasn't there.

My conclusion was that there is a reason 23mm is the norm.

mattm

I don't think it will make a difference.

flashpoint145

My racing wheelset has 700c x 20mm tires on it. No problem.

My training wheelset is 23, however.

jwible

Avocet's baby!

I think my Corse tubulars were 21s. Training on 25s now and have 23s on the 404s.

adam_mac84

Continentals that I had on my bontragers were 22mm... I had no problems, i bet 21 would be fine too