Cycling UK Forum

Bmblbzzz wrote: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!

In some of those conditions you'd push anything short of a motorbike!

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.

For the record Cross(Cyclocross?)bikes bear no resemblance to a Vaya or a dedicated tourer other than big clearances.

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

That depends on the time of year and which part of the country you live or ride.

gloomyandy wrote: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.

What's there to be gloomy about?

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.

Talk to any cyclist...........

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.

I think we're singing from the same sheet,in that there's a lot of 'protracted' wisdom and less tried and tested for what is best for the individual.

irc wrote:

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.

JH did some wind tunnel tests with and without a huge barbag,it came up with some surprises:- https://janheine.wordpress.com/2012/05/ ... -bicycles/

irc wrote:

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....

there two of them, and each one has a front and a back, (so there are four bits pushing through the air) and the top of the wheel is going at twice the speed of the bike; aerodynamically speaking, wheels are quite a big deal. Maybe it was an overestimate (as I originally suggested) but my point is that quite small differences in size (for any given shape) are likely to be disproportionate in effect.

The aerodynamics of luggage is usually pretty hopeless too really. It wouldn't be so very difficult to design luggage that would make you faster, not slower!

If you ask a typical cyclist (even a touring cyclist) if they would like to go faster for the same effort, you'd get the same answer almost every time, yet we are all still riding round on machines that (aerodynamically speaking) have not moved on much in the last 100 years.

BTW JH's wind tunnel tests were IMHO flawed, to say the least; most cyclists are effectively riding into a front/crosswind, most of the time, something that his tests didn't acknowledge. He also claimed that his mudguards didn't make any significant difference, nor did the width of the tyres, etc etc, whereas others have found that differences of this sort make differences of the order of tens of watts.

cheers

pwa wrote: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.

That isn't my impression, except where it's been a shorter event organised by a road club and the majority of riders have been from that club. My experience may be skewed by the majority of local events being run by CTC groups and people riding what they would on an on road summer CTC run. Majority still steel with mudguards and a fair mix between DP and cantis. Of the people I know who are a bit keener than the occasional rider, the preference still seems to be in what we're talking about as an Audax bike, though increasingly likely to be in ti.
It's an impression rather than data, I'll start counting bike types!

reohn2 wrote:

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.

For the record Cross(Cyclocross?)bikes bear no resemblance to a Vaya or a dedicated tourer other than big clearances.

I think this depends more on whether you tend to "split" or "lump".

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

That depends on the time of year and which part of the country you live or ride.

There are some gravel tracks round here but those tend to be the better maintained and more frequented ones, like the Fosse Way. Most bridleways here have a lot of clay. There are metalled farm and forest tracks, of course, but we don't tend to have the gravel (metalled) public roads that are common in eg NZ (part of National Highway 1 was still gravel when I was there), parts of Europe or, judging from this stuff, America. Yes they exist, but they are outnumbered by mud IME. Must be regional variation, as you say.

Bmblbzzz wrote:I think this depends more on whether you tend to "split" or "lump".

We're going to have to agree to differ then.
In my world,Cross bikes a one to one and a half hour maximum,race bikes with aggressive geometry,short WB,horizontal TT's to shoulder the bike easily and light as possible.That's not to say they can't be used for anything else,but long rides they're not designed for and comfort isn't in their remit.

That depends on the time of year and which part of the country you live or ride.

There are some gravel tracks round here but those tend to be the better maintained and more frequented ones, like the Fosse Way. Most bridleways here have a lot of clay. There are metalled farm and forest tracks, of course, but we don't tend to have the gravel (metalled) public roads that are common in eg NZ (part of National Highway 1 was still gravel when I was there), parts of Europe or, judging from this stuff, America. Yes they exist, but they are outnumbered by mud IME. Must be regional variation, as you say.[/quote]
Mudplugging is best done on MTB's,if the terrain is very bad.
Gravel and Touring bikes handle an element of mud but not an all day mud fest.
I ride my Vaya(s) on tarmac and most off road conditions I ride my MTB,however in the winter we've just had I'd choose my routes a bit more carefully,or do car assist and ride trails on the MTB.

reohn2 wrote:

Bmblbzzz wrote:I think this depends more on whether you tend to "split" or "lump".

We're going to have to agree to differ then.
In my world,Cross bikes a one to one and a half hour maximum,race bikes with aggressive geometry,short WB,horizontal TT's to shoulder the bike easily and light as possible.That's not to say they can't be used for anything else,but long rides they're not designed for and comfort isn't in their remit.

But we're not talking about cross bikes!* I said gravel bikes were (IMO) somewhere between crossers and tourers, or indeed between cross and "endurance road". Combining the comfort of the latter wth the clearances and off-road ability (some of it) of the former.

*Though we have things like the Specialized TriCross, which I don't think is going to appeal to any serious cyclocrosser, but is clearly intended to draw on, or make an appeal to, those origins and take them a step or two towards touring, commuting, while retaining off-road ability. Bike Radar says:

We’re big fans of the natural versatility of ’crossers – their tough but light frames house big clearances for high-volume touring tyres, or road slicks with room for mudguards – and Specialized have taken that mongrel versatility one step further.

http://www.bikeradar.com/gear/category/ ... -09-33640/
Not that you should necessarily believe them, mind!

Anyway, as you said, agree to disagree...

PH wrote:

pwa wrote: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.

That isn't my impression, except where it's been a shorter event organised by a road club and the majority of riders have been from that club. My experience may be skewed by the majority of local events being run by CTC groups and people riding what they would on an on road summer CTC run. Majority still steel with mudguards and a fair mix between DP and cantis. Of the people I know who are a bit keener than the occasional rider, the preference still seems to be in what we're talking about as an Audax bike, though increasingly likely to be in ti.
It's an impression rather than data, I'll start counting bike types!

It does vary from event to event. And thankfully Audax is one type of event where you can turn up on any roadworthy bike and not feel too out of place. My impression is that Sportive type bikes (mainly carbon composite framesets) are becoming the default type for those new to Audax, and for many who aspire to a fast ride. But there are certainly still a lot on Mercians, Dave Yates, etc. In a way, a Sportive bike can make sense if your calendar includes both Audax and Sportive rides. And if you can live with flimsy make-do mudguards or no mudguards at all. Disc brakes are becoming a common sight, though I don't yet have a feeling for how far that will go. Will they become the majority on Audax events of the near future?

pwa wrote:Disc brakes are becoming a common sight, though I don't yet have a feeling for how far that will go. Will they become the majority on Audax events of the near future?

Perhaps not in the “near future”. Eventually, yes. Disc brakes are appealing to many cyclists and the manufacturers would push discs regardless, since they’re not compatible with existing bicycles and therefore represent a massive money-making opportunity.

Hopefully rim-braked frames and components will remain available for a long time for those who stubbornly prefer them.

A couple of weeks ago I saw, in use, a bike with (a front brake (it was fixed so no rear) that was a little rod-operated pad pushing on the top of the tyre. 1920s, I think. There's hope for rim brakes for a long, long time yet!

Samuel D wrote:Hopefully rim-braked frames and components will remain available for a long time for those who stubbornly prefer them.

I don't think there's are risk of rim brakes every becoming obsolete for a very long time yet

Bmblbzzz wrote:A couple of weeks ago I saw, in use, a bike with (a front brake (it was fixed so no rear) that was a little rod-operated pad pushing on the top of the tyre. 1920s, I think. There's hope for rim brakes for a long, long time yet!

Though no hoe for any reasonable stopping power from that brake .
A good job it was fixed

I cant see rim brakes dying anytime soon, aren't BSO's still with rim brakes?

I can't seem to make my mind up whether rim brakes are still worth getting now if I was going to buy a new bike, especially as the weather here is so variable. If I lived in somewhere warm and dry, disc brakes would not get a look in for a road bike.

samsbike wrote: ... I can't seem to make my mind up whether rim brakes are still worth getting now if I was going to buy a new bike, especially as the weather here is so variable...

it rather depends what you want your new bike for, doesn't it?

People seem to get tramlined into a mindset of choosing between 'rim brakes vs disc brakes' but this isn't really a fair reflection of the choices on offer.

There are such things as coated rims that don't wear out, and hub brakes. Depending on what you want your bike for, either could be a better choice than 'normal rim brakes' or disc brakes.

cheers