[python] Re: Tire for Breakfast?
- From: Dirk Bonné <dirk.bonne@xxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Fri, 29 Apr 2011 13:25:06 +0200
Hi George,
I knew some of all that. But still pump them up to 5.5bars. It's all in
the mind.
DirkB
On 28.04.2011 00:15, George Durbridge wrote:
> Dirk,
>
> You will have looked into this, but Schwalbe recommend running Big
> Apples at much lower pressures. You do get lower rolling resistance on
> smooth surfaces by increasing the pressure from 2.5 bar to 5 bar, but
> not a lot. See the second graph on this page:
>
> http://www.schwalbetires.com/tech_info/rolling_resistance
>
> The information on that page is obviously dated, and Schwalbe have
> reduced rolling resistance on many of their tyres in the last few
> years.
>
> The stress in the rim is related to tyre pressure - as far as I can
> tell, it is directly proportional. Schwalbe advise against using high
> pressure in wide tyres on narrow rims:
>
> http://www.schwalbetires.com/tech_info/tire_dimensions
>
> There is another factor, which may not apply to you. On some of our
> roads, which are fairly rough, particularly the unsealed ones, we get
> lower rolling resistance by lowering tyre pressure. At the lower
> pressure the tyre deforms around a pebble, which takes less work than
> lifting the bike over it. This has been checked by roll-down tests on a
> hill with a roughly-sealed road: Marathons at 80 or 90 psi were quicker
> than the same tyres at 100 psi (roughly 5.6, 6.3 and 7 bar).
>
> I don't know of any measurements, but on a very rough gravel lane, I
> found it easier to push Big Apples at 2 bar than at higher pressures.
>
> Regards,
>
> George
>
> On Wed, 2011-04-27 at 14:25 +0200, Dirk Bonné wrote:
>> Hi George,
>>
>> quite high. The BAs are specified up to 5bars, but I usually pump up to
>> 5.5 or even 6bars.
>>
>> I broke in total 3 rims. The one in the picture held less than a year
>> and is may be a faulty fabrication. The other 2 broken rims were
>> installed on my baby python (RIP), and were quite old: about 10years and
>> had considerable wear on the flanges (V-brakes). I may have ridden 4
>> years with BAs on these rims, before that marathon 35-406 or
>> vredresteins monte carlo 37-406 (my favorites at the time).
>>
>> I have a new rim now: "schürmann reflex 19"
>> (http://www.schuermann-rims.com/rims/index.php?id=21) and they are
>> specified for a 62mm tire ( no pressure specs though :-( ).
>>
>> Dirk
>>
>>
>> On 26.04.2011 23:16, George Durbridge wrote:
>>> Dirk, the rim cracking looks bad: what pressure are you using in your
>>> Big Apples?
>>>
>>> On Mon, 2011-04-25 at 15:15 +0200, Dirk Bonné wrote:
>>>> Arggh wrong picture, it was this one I wanted t show:
>>>>
>>>> https://picasaweb.google.com/dirk.bonne/Pythoon#5591445038290460706
>>>>
>>>> On 25.04.2011 15:13, Dirk Bonné wrote:
>>>>> Be aware that the rim must be up to the extra force caused by a big
>>>>> apple (the force on the rim goes up lineary with the width of the
>>>>> tire). I have broken in total through 3 rims, they split open either
>>>>> at the flange
>>>>> (https://picasaweb.google.com/dirk.bonne/Pythoon#5501268362855244498 ),
>>>>> or in the middle where the holes to access the nipples are drilled.
>>>>>
>>>>> The solution is to have a good quality rim that is wide enough. Big
>>>>> apples are still worth the trouble, cause it is much more forgiving
>>>>> when riding through potholes.
>>>>>
>>>>> DirkB
>>>>>
>>>>> On 25.04.2011 11:28, Gerald wrote:
>>>>>> Hi All,
>>>>>> Thank you for all the feedback! Good to hear that you do not
>>>>>> experience the same extreme tire wear. Gives me also the
>>>>>> confidence it is just the cheap tire, not the concept.
>>>>>> The alignment is OK, maybe could be better but we are talking
>>>>>> about 2-3 mm here.
>>>>>> Guess I will try either the big apples or the marathons and see
>>>>>> how they last.
>>>>>>
>>>>>>
>>>>>> Best regards
>>>>>> Gerald
>>>>>>
>>>>>> On 21.4.11 20:58 , Dirk Bonné wrote:
>>>>>>> Hej Gerald, I always put on big apples (50-406) on my python
>>>>>>> (pythoon now). There is no extraordinary tear on them - in fact
>>>>>>> the tires never wear out, because I have always need to replace
>>>>>>> them from the cuts made by the silica stones, instead of the
>>>>>>> wear of the rubber.
>>>>>>>
>>>>>>> Dirk
>>>>>>>
>>>>>>> On 21.04.2011 13:00, bepb@xxxxxx wrote:
>>>>>>>> Hi,
>>>>>>>> five weeks after roll-out off my 20" python, the tire off the
>>>>>>>> front wheel is finished. Either the tire was rubbish from the
>>>>>>>> start or the bike eats then for Breakfast, or both. The tire
>>>>>>>> was more or less new.
>>>>>>>> I unterstand that both the frontwheel drive as well as the
>>>>>>>> smaller size will add to tire wear, but this seems a bit
>>>>>>>> extreme.
>>>>>>>> I now wonder which tire to buy. Just again the cheapest
>>>>>>>> availabe or is there some type that will last longer? Any
>>>>>>>> expiriences?
>>>>>>>>
>>>>>>>> Gerald
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
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