Path: ...!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: Roger Merriman <roger@sarlet.com>
Newsgroups: rec.bicycles.tech
Subject: Re: Science of cycling still largely mysterious
Date: 26 May 2025 10:02:42 GMT
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Frank Krygowski <frkrygow@sbcglobal.net> wrote:
> On 5/25/2025 4:41 PM, Roger Merriman wrote:
>> AMuzi <am@yellowjersey.org> wrote:
>>> On 5/25/2025 1:45 PM, Wolfgang Strobl wrote:
>>>> Am Wed, 21 May 2025 19:17:51 -0400 schrieb Frank Krygowski
>>>> <frkrygow@sbcglobal.net>:
>>>> 
>>>>> On 5/21/2025 4:13 PM, Roger Merriman wrote:
>>>>>> zen cycle <funkmasterxx@hotmail.com> wrote:
>>>>>>> 
>>>>>>> A full suspension bike is far more efficient over rough terrain in terms
>>>>>>> of speed and comfort.
>>>>> 
>>>>> I dimly recall an article in _Bicycling_ magazine (before it effectively
>>>>> morphed into "Buycycling") that documented the measured increase in
>>>>> downhill speed of a suspended bike compared to a rigid bike. At that
>>>>> time, it was an unfamiliar concept.
>>>> 
>>>> Problem is, some people generalize the fact that a good suspension
>>>> increases downhill speed on some undergrounds to circumstances where one
>>>> or all of these preconditions do not apply.  Suspension adds weight and
>>>> converts some of the potential energy to heat. When riding downhill,
>>>> additional weight has essentially no disadvantage, it might even help.
>>>> On rough underground and at speeds where air resistance is the main
>>>> parameter, helping the rider to hold a better aerodynamic position has
>>>> more effect than that little bit of energy loss.
>>>> 
>>>> Almost nothing of all that applies while riding on reasonably flat
>>>> ground or uphill.  Some modern wider tires have lower rolling resistance
>>>> than narrow high pressure road tires of the old and offer enough
>>>> suspension for most roads that aren't not completely broken.
>>>> 
>>>>> 
>>>>>> Indeed doesn’t take a particularly rough gravel road for my MTB suspension
>>>>>> and tyres to make it a faster bike, vs the Gravel bike be that my times on
>>>>>> Strava or unfortunate Gravel riders on the Ridgeway etc.
>>>> 
>>>>> And in the past few years, many people have realized that it takes very
>>>>> little roughness to make wider, cushier tires valuable for increasing
>>>>> speed.
>>>> 
>>>> Not necessarily. In recent years, some wider tires have become better in
>>>> terms of rolling resistance at lower pressure and without compromising
>>>> puncture resistance. It's not that people have recognized something that
>>>> has always been the case. The wider the better doesn't apply, either.
>>>> The optimum has only shifted a little, again.
>>>> 
>>>> Roads degrading faster due to heavier vehicles might be a reason, too.
>>>> 
>>>>> Bumping the rider about has serious energy costs.
>>>> 
>>>> Of course.
>>>> 
>>> 
>>> 
>>> Offroad cyclists (I am not among them) tell me that for all
>>> suspension's weight and sloppiness, they cannot brake or
>>> turn with a wheel in midair so suspension is necessary for that.
>>> 
>> Even on the flat ground suspension is well fast, I regularly pass Gravel
>> folks on the Ridgeway which is one of the older roads in the uk, it’s not
>> technical it’s essentially a gravel road, but the MTB just flows and isn’t
>> kicked about like the gravel bikes are.
> 
> I once knew a local guy, a club member, who closed down his bike shop to 
> become a full time professional bike tourist. He got a job with a large 
> bike touring company, where he spent the entire year riding, leading 
> paying customers on bike tours. This was in the late 1990s, IIRC.
> 
> On one trip the group he was leading was passing through our area. 
> Someone organized a club ride to meet up with them, so I got to see the 
> bike he had chosen for his job. It was unlike anything he used to ride 
> before. As I recall, it had undersized wheels (maybe 24 inch?) that were 
> very aero (trispoke, I think), an aero bar, and full suspension.

That was sort of the Moulton idea, had short travel eslatomers? And small
high pressure tyres is apparently a Gravel version though much like the
Brompton (sans suspension) i suspect it’s off road performance will be
fairly limited.

Roll over of bigger tyres seems to matter hence racing XC and DH MTB has
largely moved to the 29er size.
> 
> The aero benefits were easy to understand, but I think for long mileage 
> day after day, he learned that the benefits of not being as jostled by 
> bumps exceed the energy losses of suspension bits heating up.

I’m guess heating up was typo? As heat isn’t really a factor unless you’re
really pushing hard such as repeated DH runs or similar.
> 
> ISTM that would be one of those tradeoffs, depending on the smoothness 
> of the riding surface. But few roads are as smooth as we'd like.
> 
Suspension be that within the tyre or active suspension is a boon, I notice
the difference on the commute between Old School roadie and it’s 28mm tyres
and the converted MTB rolling on 50mm tyres, the old MTB is a plush ride
and potholes etc can largely be ignored and those that I would I’d
absolutely avoid in a car! It’s a slow old beast but that’s down to its
relaxed position and weight.

The old school roadie I do need to be more active about potholes and so on,
it’s also a bit faster due to weight and position which also encourages
faster vs relaxed ride.

Aka I pick and choose the bike I think will be most useful for each day, so
last Friday I needed to cross some across London within a fairly short time
frame, public transport had no hope, and car would of been painful! So old
school roadie it was!

Roger Merriman