Quoted message said:I'm looking for a 25mm tyre and have been impressed with the comments
from Jobst Brandt
Quoted message said:and others on the Avocet road tyre. They are completely slick,
durable and have low
Quoted message said:rolling resistance as far as I can see. However, I cannot find them
here in the UK.
Quoted message said:Also, athough they appear to be durable, I'm not clear on how well
they would handle
Quoted message said:my daily commute through London where I regularly ride over glass.
Can anyone recommend a completely slick tyre that would be suitable?
You might try Continental Ultra 2000, on sale $14.95 wire bead at
Performance or Nashbar, which for the same size seems to have slightly
thicker central rubber that doesn't go as high up the sidewalls. Thus
less durable on the sides, slightly more down the middle.
Consider this table, which in a fixed-width font works:
20 23 25 28 32 35 38
Avocet C12 235 255 300 390
CII 330 370 395 480
Michelin Dyn 265 280 300 335 370
SP1000 280 310 330 350 380
Conti UG 280 300 320 330
Conti U2000 240 270 310 360
Top Touring 490 550
(Note: these all for wire bead, but I believe I estimated the 28 for
the U2000 by adding 50g from the Kevlar bead version, and the specs
other than 23 for this tire were from Performance or Nashbar. All
others from the manufacturers . If someone has better specs please
supply.)
You will see first of all the massive difference between even heavy
duty road type tires, and a touring/commuting tire like the TT.
Correspondingly large difference in puncture resistance and wear.
Second, if you plot these, you will see very different design
philosophies: the Avocet slicks (C12) increase quasi-exponentially in
weight while e.g. the Avocet Cross II, Michelin Dynamics, and Conti
SuperSport 1000s increase quasi-linearly, and finally the Ultra
GatorSkins level off- i.e. users of narrow UG's will find them
relatively heavy duty, users of the wide ones will find them relatively
light duty. The Ultra 2000s have 57 tpi casings, close enough to the
Avocet 66 tpi for 28mm+ (although nylon vs. rayon) to make one suspect
the weight differences correspond to puncture resistances. 25mm and
below Avocets are 127tpi and so will be lighter for same rubber-
although lighter casings are therefore not as strong. Dynamics are
33tpi, SuperSports 28tpi.
Note also that the 32mm Avocet C12 is a very unusual tire, even within
the Avocet range. Compare:
Carbon 12 Cross II
28mm 300g 330g 28mm
32mm 390g 370g 32mm
The 28mm C12 Avocet is lighter than the correspoinding Cross II Avocet,
as one would expect; but at 32mm the story changes, the road slick all
of a sudden becoming heavier than the corresponding supposedly heavy
duty tire. The corresponding IRC Road Winner going from 27x1-1/8 (290)
to 27x1-1/4 (335) does not show this sudden increase.
It would be very useful if someone could compile a corresponding table
of tread thicknesses for these tires. I believe the U2000 has the
thickest rubber down the middle, the Avocets the most overall. As for
rubber hardness, this is essentially a matter of how much carbon is
used and I suspect these are all comparable.
Another tire you might like which I didn't include in the table because
it is only available in 23 and 25 is the Michelin Carbon. It is unusual
in having one extra full bead to bead 127tpi carbon-rubber reinforced
layer. Thus one might expect it to be more puncture and cut resistant
than the corresponding Avocets (sorry, don't have the weights on hand).
Back to puncture resistance: you can't get it with a lightweight tire.
If you are worried about glass Kevlar might help, but it will make the
tire ride slower. Thicker rubber is where it's at and there are some
routes and some jobs where for commuting you just need something like a
Top Touring, Vittoria Randonneur, or the ultimate, Shwalbe Marathon
Plus (1cm of rubber to tube).
