Tyre size

GerryM01

Hi, I am looking to change my winter tyres on my commute bike (hybrid) to something a bit more slick.
The tyre size currently is 700x35c.
Do i need to stick to 35c or can I get something slimmer?
Any help/advice gratefully received

Sleeper Service

What size are your rims? It should be on the wheel.

This helps:

http://www.betterbybicycle.com/2014/04/ ... heels.html

The Rookie

In most cases you'll be able to go slimmer, a normal Hybrid rim of 17 or 19mm (internal width) will take down to a 25mm tyre, though unless you are very fast a 28mm is probably a better option.

GerryM01

Thanks for the advice

Initialised

Generally bigger tyre, same tread means more weight and comfort.

Don't worry too much about size tread pattern determines uses.

Slick - Road
Slick with channels/file tread at the edge - wet road/poor surfaces
File - Bad road, gravel, hardpack
Semi Slick (file centre, knobbly edge) - As above plus the odd bit of mud/loose surfaces/larger grain gravel
Metal Studs - Ice (Snow Studs are bomb proof winter tyres)
Anything more is for CX or MTB use, purely off road use, will just slow you down anywhere else.

I'm running 25mm Specialized Roubaix tyres - Slick centre, file edge, they handle all but proper off road trails comfortably.

The Rookie

'John Thomas' nicely sums up the quality of that post....

asprilla

Initialised wrote:

Slick - Road
Slick with channels/file tread at the edge - wet road/poor surfaces

Slicks provide the best grip on we roads, file patterns do not.

Car tyres don't have grips, they have channels to remove water which would otherwise build up in front of the tyre and then cause it to aquaplane. It's a function of the width of modern car tyres and the speed at which they travel.

Given a bike tyre's relative width you'd need to be doing about 200mph to aquaplane so having a file tread (or any other tread) on a road bike is simply reducing your contact patch and so reducing your grip.

Most hybrid tyres have treads because consumers expect them and will pick treaded tyres over slicks due to the above misconception.

jamesco

I love the 35c Kojak slicks on my hybrid:

• light
• very comfortable
• 
  good puncture resistance (only 3 in 5,000 miles and one was from a 50mm screw that would have done M+, too)
• reasonably long-lasting
• reflective side-wall.
• reasonably priced (on ebay and inevitable sales)

They also look pretty cool, as far as tyres go

asprilla

Kojaks are good tyres that roll well, but they do keep the weight down and achieve their low rolling resistance by having very thin side walls. I have them on my Brompton and I used to run them on my SSCX.

The Rookie

The only purpose of the tread pattern is to let you know when the tyre is nearly worn out.

I have Conti sport contacts which have a tiny tread weave, won't clear any water.

imatfaal

Asprilla wrote:

Initialised wrote:

Slick - Road
Slick with channels/file tread at the edge - wet road/poor surfaces

Slicks provide the best grip on we roads, file patterns do not.

Car tyres don't have grips, they have channels to remove water which would otherwise build up in front of the tyre and then cause it to aquaplane. It's a function of the width of modern car tyres and the speed at which they travel.

Given a bike tyre's relative width you'd need to be doing about 200mph to aquaplane so having a file tread (or any other tread) on a road bike is simply reducing your contact patch and so reducing your grip.

Most hybrid tyres have treads because consumers expect them and will pick treaded tyres over slicks due to the above misconception.

Road / tyre Friction is not really related to contact patch size either - many people refuse to believe it, but the simple formulation that frictional force is the coefficient of friction (depends on only the materials) multiplied by the normal force holds very very well for rubber. There are other reasons you want a larger contact patch; wear and tear, heat build up, less likelihood of point being on a moveable object on road etc - but the simple frictional force is not dependent on the size of the patch of rubber on the road.

asprilla

imatfaal wrote:

Asprilla wrote:

Initialised wrote:

Slick - Road
Slick with channels/file tread at the edge - wet road/poor surfaces

Slicks provide the best grip on we roads, file patterns do not.

Car tyres don't have grips, they have channels to remove water which would otherwise build up in front of the tyre and then cause it to aquaplane. It's a function of the width of modern car tyres and the speed at which they travel.

Given a bike tyre's relative width you'd need to be doing about 200mph to aquaplane so having a file tread (or any other tread) on a road bike is simply reducing your contact patch and so reducing your grip.

Most hybrid tyres have treads because consumers expect them and will pick treaded tyres over slicks due to the above misconception.

Road / tyre Friction is not really related to contact patch size either - many people refuse to believe it, but the simple formulation that frictional force is the coefficient of friction (depends on only the materials) multiplied by the normal force holds very very well for rubber. There are other reasons you want a larger contact patch; wear and tear, heat build up, less likelihood of point being on a moveable object on road etc - but the simple frictional force is not dependent on the size of the patch of rubber on the road.

Indeed. Just read this excellent article on the subject. Worth reading to the end.

http://www.stevemunden.com/friction.html

The Rookie

Not quite true, the friction generated by tyres is far from constant, increased surface loading and changes in temperature both change the coefficient of friction, so if you are overworking a narrow tyre such that the coefficient of friction it produces is falling then a wider tyre which would maintain its coefficient of friction better will have more grip, that is why race cars have wider tyres. If it were true race cars would all run narrower tyres for the same grip and less aerodynamic drag.

When it comes to bikes I agree its rare to overwork the tyres, an obvious exception though would probably be Downhill. It would be possible on a road bike on a fast decent with lots of turn to start to overheat the tyre to the extent that the coefficient of friction starts to fall, but a narrower tyre rolling faster (less aero drag) would probably still get down the hill faster despite not having quite as much grip.

That article briefly covers it when it says "until the tire overheats and gets slippery because it can't absorb and dissipate heat like the big tire does" but conveniently ignores that the coefficient of friction is changing all the time due to load and heat.

imatfaal

Asprilla wrote:

imatfaal wrote:

Asprilla wrote:

Initialised wrote:

Slick - Road
Slick with channels/file tread at the edge - wet road/poor surfaces

Slicks provide the best grip on we roads, file patterns do not.

Car tyres don't have grips, they have channels to remove water which would otherwise build up in front of the tyre and then cause it to aquaplane. It's a function of the width of modern car tyres and the speed at which they travel.

Given a bike tyre's relative width you'd need to be doing about 200mph to aquaplane so having a file tread (or any other tread) on a road bike is simply reducing your contact patch and so reducing your grip.

Most hybrid tyres have treads because consumers expect them and will pick treaded tyres over slicks due to the above misconception.

Road / tyre Friction is not really related to contact patch size either - many people refuse to believe it, but the simple formulation that frictional force is the coefficient of friction (depends on only the materials) multiplied by the normal force holds very very well for rubber. There are other reasons you want a larger contact patch; wear and tear, heat build up, less likelihood of point being on a moveable object on road etc - but the simple frictional force is not dependent on the size of the patch of rubber on the road.

Indeed. Just read this excellent article on the subject. Worth reading to the end.

http://www.stevemunden.com/friction.html

I had just book-marked that very page :-)