i ran both actually... the rear worn out and i could not find replacement.. took the front and bought it a new 23

I have the same question too, any particular reason to use wider tyres...anything to do with weight of the rider.. ??Alberto and Sagan on either ends of the scale as an eg. comes to mind.

it is tested to have lower rolling resistance due to lesser tire drop... and you can run lower pressure so iy rolls over road irregularites better improving comfort

I read somewhere that they recommends 15% tyre drop (against gird height) for optimum comfort and performance. Do you buy this theory? Therefore a 23c should have lower rolling resistance compared to a 25c base on surface contact, although minimal.. ya ka?

This post has been edited by Mac Wai: Dec 8 2012, 02:05 PM

ive been wondering what tyre pressure do you guys use on normal ride?

for me the comfort one is 90 psi..I used to ride with 110psi for every ride but it gaves me a harsher ride especially when I changed to FR0, hence I lowered it down to 90psi for every ride..

Only here in my new place where they have smooth surface for the whole 85km loop that I pumped up back to 110psi for every ride as the smoother the surface, the more higher I can use the pressure for a better speed...correct me If i'm wrong

front 7bar, rear 8bar.

actually, you got it reversed...

the 25 will drop less hence having a smaller contact patch reducing friction and rolling resistance

Today I joined a group of riders for Bentong (Pahang) ride.

Sent my bike for that full service including wheel truing. although I can't slam the stem due to no available / suitable headset everywhere in this country I still asked them to cut the excess steerer tube.

And I bought this Schwalbe Ultremo ZX 25c..without knowing if my bike can fit the new tyre width or not as my bike is at another shop..2 of my extra spare tubes not suitable for 25c..luckily the other 2 tubes is suitable

hopefully it fits well!!!!!

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Added on December 8, 2012, 8:47 pmTire pressure reference:



This post has been edited by mrjgx: Dec 8 2012, 08:47 PM

Killing two birds with one stone....



Feel more comfy and less like mushroom head.



Spent 3 hrs in my bathroom trying to get the best setting for my new helmet. Totally different from my previous helmet.

Keep getting cramp on my foot when i stand and pedal.... Hmm its it because i did not have proper warm up of the foot?

This post has been edited by minizian: Dec 8 2012, 09:28 PM

i think that statistic doesn't prove the point of performance...

This is a test done on a Schwalbe Durano, not sure who did the measurement but it was featured in velonews


All with frame clearance aside. As you can see, the wattage used on the tires decreases with width. 25mm would be optimal due to the minimal additional weight compared to the 28 and 32mm. Also, the 25mm would still be compliant with the wider aero rims of today and still get quite good aero measurements compared side to side with a 23mm.

in fact, if you read. Zinn mentions that the drop in pressure actually reduces rolling resistance which is very counter intuitive
http://velonews.competitor.com/2012/03/bik...l-faster_209888

the only problem is being the wider tires do ruin some aero efficiencies...


you can see that using the same 303 firecrest rim.. the 23mm does offer better wind cutting performance than the 25mm.. which zipp claims that it over-rides the saving in wattage from rolling resistance reduction...

so, it really depends on how you see it...

on one hand, you get slight comfort improvements and lesser rolling resistance

on the other, you get maybe more turbulent airflow behind the wheels and increase air resistance...

again, you have to weigh your options based on what you ride more...

This post has been edited by butthead: Dec 9 2012, 01:25 AM

around my fifth ride. 12km, 20kmph average. ok ma?

boss, what about using narrow rims like ksyrium with ride 25 tyres? i notice fulcrum rims are wider than ksyrium. ksyrium sl rim width edge to edge is (19f/20r)

u guys really know how to have fun... that is what cycling is all about ... especially foldies...

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Added on December 9, 2012, 12:47 pmits not about the speed... more importantly enjoy your ride...

you dont ride to train for competition rite?

This post has been edited by butthead: Dec 9 2012, 12:47 PM

Yesterday was a mix bikes ride. There are foldies, mountain and road bikes. It was fun but hot. We started at about 7am but I left early at 2pm. The others were still having durian near the waterfall. They went for late lunch after too.

Looking fwd for more of such ride. Cycling in big group is fun and I feel safer too cause traffic can see us clearer.

Butthead, you are right the chart I posted is not showing any value on performance just to how the riders weight and the tyre pressure suitable.

Anyway Garmin Edge 900 is due out soon..luckily I didn't get the 800 else should be banging my head on the table

in terms of airflow or crr?

of course it makes more sense running wider 23mm rims as that allows the tire sidewall to sit more vertically upright as opposed to narrower rims... that should improve the tire to road interface much better theoratically...

all else, a wider 25mm will still roll better especially under a heavier rider... except if you want to consider aero properties

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Added on December 9, 2012, 12:58 pmslow rides and makan makan rides is always the enjoyable rides....

too bad i dont have the patience

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Added on December 9, 2012, 12:59 pmgetting gatal aren't you?

This post has been edited by butthead: Dec 9 2012, 12:59 PM

Haha my friend and I planned to do that whatever cycling tours available. Perhaps the TDF routes, or Rapha cycling tours etc since we already halfway to Europe..

Hence the need of a GPS enabled device. Maybe need 1-2 year of planning, for fitness and also financial.

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Added on December 9, 2012, 12:47 pm

its not about the speed... more importantly enjoy your ride...

you dont ride to train for competition rite?

[/quote]

I might consider to join a local competition soon. But would love to join some group cycling.

saw my first fat bike the other day ..