Cycling UK Forum

531colin wrote:

honesty wrote:.......... I want the same bike, just with larger clearances for bigger tyres..........

^^^^^THIS...This is why its lunacy to use a FAULT of road STIs and dual pivot sidepulls to define an "audax" bike......Poor clearance is a FAULT........unless somebody can demonstrate that its a benefit.....and that is a challenge.
Why not have a bike where you can fit 35mm tyres if you want to?....you don't have to, you can use 23s in a bike with room for 35s.....but you can't do it the other way round!

I completely understand this way of looking at it, and I largely agree. I suppose I differ from some here in that with a springy saddle and cushioning bar tape I find a bike with 25mm tyres can feel fine if those tyres are particularly supple (which seems to mean expensive) and not pumped up too hard. I am able to achieve that "sweet spot" of comfort and speed. But yes, it would be simpler if the brakes (I use some ancient RX100s) were not so limiting when using mudguards. Trouble is, I like the brakes. Compared to the cantis I'm used to on other bikes, the dual pivots are very good. Power is fine, though I do sometimes have to pull hard in extreme situations. Modulation / feel is great. I always know how much pressure is needed. And maintenance is negligible. Change the pad inserts once in a while and (if I'm being fussy) wipe muck off.

But for those who cannot get 25 /28mm to work for them, Colin's disc bike prototype is the kind of thing that is needed. I just worry that the stiff fork may mean that some of the advantage of larger tyre volume is lost.

meic wrote:If I had to have just one bike to do everything it would be either a light tourer on an Audax. Looking back over the six years since I chose the light-tourer instead of an Audax, I cant say that it made that much difference and I dont think it was a better option than the Audax bike, just a different option.
I bet the affluence of the cycles at a Audax is rather small per mile and in comparison to the costs of petrol and accommodation involved in them being there.

That depends on what your 'everything' entails and the definition of light tourer compared with Audax bike.

For me the everything bike is a 12kg disc braked,35mm Hyper shod,low geared 20" to 90" 3x8sp, do almost anything very well (except full MTBing) bike.
An extremely capable machine that I'd have worries about riding Audax type rides on,though TBF in the last couple of years I rarely ride over 100miles.

fastpedaller wrote:That's an interesting observation re 'go with the flow'. I suspect that most of the flow is borne out of experience of the type of event. Incidentally do you use wire-ons for TT's or tubulars? - From my experience (although the difference is less than it was) tubs are far superior for Time Trialing.
Now I'll put the cat amongst the pigeons and say why has nobody suggested a specific bike for SPORTIVES
(feel free to ignore my comment if it's too far off topic)

The big manufacturers market these as "Endurance" or some similar term, eg Trek Domane. You see a lot of these on audaxes and some of the pros ride them on events like Paris-Roubaix.

meic wrote:So there are three of us here who would choose to have a bike with a bit more flexibility in its tyre range and would happily ride it on an Audax instead of a standard Audax bike. I would call that an Audax+ bike.

Do you work in marketing?

We already have an increasing range of terms to describe ever more specific types of bike; or at least, bikes targeted at ever more specific niches. In practice many of these bikes look pretty flexible to me. I'm thinking particularly of "gravel" and "adventure" bikes, which have grown out of cyclocross bikes with a nod towards road bikes. Designed to be ridden pretty fast but with big clearances, and nothing to stop you fitting skinny tyres if you want – particularly as most have disc brakes. Many also take rack and 'guards. Suitable for everything from commuting to touring to the Dirty Reiver or a traditional 'cross race. Or your local club 25. You could even ride an audax on them! My point being, we really don't need yet another term for yet more segmentation.

gloomyandy wrote:
Good question. I think that in this case going as fast as possible is my main aim. However the interesting question is that given that (for me at least) riding a tt is not a very comfortable experience, given the position, the narrow high pressure tyres, riding 10/25 miles pushing as hard as you hope you can, would the extra gain in comfort from a wider tyre, counter the possible loss in speed due to any increase in air resistance. After all having a less uncomfortable ride might let me produce a few more watts or at least let me produce the few I do for a little longer! I guess the length of the event may come into this as well. I generally ride 10 and 25 mile events, perhaps on a longer event the balance might be different?

Anyway, getting a little off topic, so back to Audax!

Air resistance is a minimal to nothing calculation on 10 to 25mile ride unless you're consistantly over 25mph throughout and then it won't be much.
But what if,due to wornout/bad/chip n seal tarmac a bigger say 28mm compared to a 20mm rolled better due to less of a bounce factor ie; a straighter line no 'bobble' better control longer on the extensions,better faster cornering,etc?
As it's been Shakespeare's birthday this week I'll paraphrase the Bard "there could be more things in heaven and earth than are dreamt of in most people's philosophy"

It is true that Audax bikes are no longer the dominant bike type at Audax events. Sportive bikes have taken over. And if people like to ride them, fine. But the bike type that we (for now) refer to as "Audax" is a very useful, versatile machine. It will do some of things a tourer will do (and about 90% of what I use my tourer for) and act as a Sportive machine with very little compromise. And for Audax itself, it is still the best option if you prefer having full mudguards in wet weather, and you want to pack some sandwiches and a proper waterproof that actually keeps rain out. But an Audax bike could, in my view, have disc brakes for those who want slightly larger tyres. I see no reason why an Audax bike should be defined by 57mm DP brakes if there is a market for another type of brake.

ooh, I dunno about the air resistance being negligible; at about 15mph, increasing frontal area by 0.1sq m will slow you down by about 1mph, or about five minutes every hour.

Now 0.1sq m sounds like a lot, (and maybe it is), but there is an argument that 'wheels count double' (or worse) because there are two of them and they thrash through the air somewhat.

But in terms of performance gains, quite a lot of folk would trade a little bit of comfort for even half a mph speed increase, or take the speed increase and try to whittle the comfort back again some other way.

cheers

Bmblbzzz wrote:

meic wrote:So there are three of us here who would choose to have a bike with a bit more flexibility in its tyre range and would happily ride it on an Audax instead of a standard Audax bike. I would call that an Audax+ bike.

Do you work in marketing?

I don't think he does and I hope he never will,I'm confused enough as it is

We already have an increasing range of terms to describe ever more specific types of bike; or at least, bikes targeted at ever more specific niches. In practice many of these bikes look pretty flexible to me. I'm thinking particularly of "gravel" and "adventure" bikes, which have grown out of cyclocross bikes with a nod towards road bikes. Designed to be ridden pretty fast but with big clearances, and nothing to stop you fitting skinny tyres if you want – particularly as most have disc brakes. Many also take rack and 'guards. Suitable for everything from commuting to touring to the Dirty Reiver or a traditional 'cross race. Or your local club 25. You could even ride an audax on them! My point being, we really don't need yet another term for yet more segmentation.

Well actually they didn't,bike such as the Salsa Vaya were made for gravel racing in such events as the Dirty Kansa 200:- https://www.youtube.com/watch?v=YQ5QAjX ... LBZ269yc1g ,about eight years ago Salsa developed a bike that would be comfortable on such terrain,that was good for touring too(and bladdy fine job they made of it too ),big rubber,disc brakes low BB,long WB,slack angles,with take you home positive steering,bladdy comfy over the course,and great for rough stuff .
A touring bike with knobs on
Then the marketeers of the big lads got on the case,tried to emulate it,and for the most part made a pigs's ear in the process AWOL anyone .
I rest my case,and my backside,frequently on two Vayas,though not at the same time that would need two backsides which I don't need or possess thankfully

Brucey wrote:ooh, I dunno about the air resistance being negligible; at about 15mph, increasing frontal area by 0.1sq m will slow you down by about 1mph, or about five minutes every hour.

Now 0.1sq m sounds like a lot, (and maybe it is), but there is an argument that 'wheels count double' (or worse) because there are two of them and they thrash through the air somewhat.

But in terms of performance gains, quite a lot of folk would trade a little bit of comfort for even half a mph speed increase, or take the speed increase and try to whittle the comfort back again some other way.

cheers

So you're telling me 8mm will make a big or indeed any,appreciable difference in speed?
Read the rest of the post,what of the benefits of the bigger tyre?
Putting serious pressure in 20mm rubber on chip n seal/worn out/bad tarmac makes for lots of bounce factor,and we know what happens when the tyre starts bouncing...

BTW I'm not claiming any absolutes,just putting forward a theory that's already being proven in other areas of racing.YVMV

the present discussion may appear to be about 8mm difference but, like all such discussions, in the end it tends to boil down to a choice between extremes, so you end up comparing 23-25mm tyres (which can be lovely and supple) with 35-40mm tyres (which also vary a lot).

In between these two there are many compromises; many shades of grey, each little different from its neighbour. One can of course suffer 'a death by a thousand tiny cuts' by erring in either direction, by degrees.

cheers

Impressive number of people pushing in that video, and not uphill. It seems those bikes don't in fact cope that well with (that type of) gravel!

But whether you consider it a toned up tourer (with fatter tyres) or a toned down crosser (with fatter tyres) isn't that important; it's somewhere between and gets used for both and more.

Though I do think "mud" would be more appropriate for most British conditions than "gravel".

Dual pivots don't need to restrict you to 28mm tyres - only the 57mm drop ones do that. Tektro, maybe others as well, do a 73mm drop dual pivot. I have some, fitted with BBB brake blocks (the blue ones, can't remember what they are called), and they are fine - startlingy good on occasions! So you can have dual pivots, 35mm+ tyres, STI/Ergos, all with standard parts and no additional adaptors (e.g. travel agents). It just needs a frame manufacturer or two to realise!

reohn2 wrote:So you're telling me 8mm will make a big or indeed any,appreciable difference in speed?
Read the rest of the post,what of the benefits of the bigger tyre?
Putting serious pressure in 20mm rubber on chip n seal/worn out/bad tarmac makes for lots of bounce factor,and we know what happens when the tyre starts bouncing...

BTW I'm not claiming any absolutes,just putting forward a theory that's already being proven in other areas of racing.YVMV

Well I typically ride a 10 at around 27mph and a 25 at (just under, and oh would I like it to be just over!) 25mph, and at those speeds air resistance starts to add up. Oh and don't forget that most (pretty much all in my experience) TTs in this country seem to be run with a huge headwind, so for at least part of the course the relative air speed may be higher. The other issue is that it is not just about frontal area. I ride a tri spoke front wheel and a disc rear, the manufacturers of both of these tell me they have spent a lot of money refining the airflow around the wheel and that having a smooth transition from the tyre to the rim is an essential part of that. Now this is all part of the tt wisdom, I have no idea if anyone has ever tried a much wider tyre, that was my (original) point really, we tend to follow what other people are already doing. Some riders may go as wide as (shock) 23mm or even 25mm but I doubt if anyone rides with 28mm (I suspect a 28mm tyre wouldn't even fit most tt bike frames). But I agree the potential benefits of better handling and less fatigue due to bouncing over a rough road surface are intriguing.

Brucey wrote:ooh, I dunno about the air resistance being negligible; at about 15mph, increasing frontal area by 0.1sq m will slow you down by about 1mph, or about five minutes every hour.

Now 0.1sq m sounds like a lot, (and maybe it is),

0.1sq m is 10cm x 1m. So if a tyre was 1m high the width would need to go from a 700x25 to a 700x125 to slow by 0.1mph due to increased air resistance. Or if the effect is double because there are two tyres then a 700x75 tyres would slow by 0.1mph.

For tourers averaging 12-15mph I think any effect from increased air resistance from wider tyres can be safely ignored. Using a rack pack and frame bag rather than a pair of panniers would probably affect air resistance far more.

Brucey wrote:the present discussion may appear to be about 8mm difference but, like all such discussions, in the end it tends to boil down to a choice between extremes, so you end up comparing 23-25mm tyres (which can be lovely and supple) with 35-40mm tyres (which also vary a lot).

In between these two there are many compromises; many shades of grey, each little different from its neighbour. One can of course suffer 'a death by a thousand tiny cuts' by erring in either direction, by degrees.

cheers

Ah!
Man moves goalposts?
The aside discussion was a bigger tyre for TT's 20(?) was mentioned,I introduced 28s into the discussion as a theoretical alternative absolute maximum(IMO) and possibly a faster one.
Isolating tyre sizes alone in theory is a way of me trying to reach some kind of consensus on how specialised bikes,even at club level have become,and possibly why it's not always the strongest or best rider who's the fastest.The variables are many and varied,tyres are but one and I'm merely pointing out that the narrowest aren't necessarily the fastest.
BTW the chances of fitting 28s on dedicated TT bike are about the same as fitting 35s,a quart won't fit into a pint pot