Tyre Advice

[lastpubrunner]

Hi All,

I know very little about bike mechanics, so hopefully my queries won't seem to appear to be somewhat naive.

I recently purchased two road racing bikes - each about 20-25 years of age. The one bike is very highly geared, so I took it to a local bike shop to have a new rear cassette fitted (I live in a very hilly region).

I was told that since the wheel was 27", there was only a limited range of cassettes available; but they managed to fit one with a range from 28 to 12 (7 speeds) - which is just the job. I was told that if I had 700c wheels fitted, there would be a much greater range to choose from.

When I got home, I was looking over the bike and couldn't help but notice that the tyres fitted are Bontrager race lite 700 x 23. Does this mean that I have 700c wheels ? (The wheels are black Mavics, but I see no way of identifying the size).

Confused, I decided to look at the other bike; this also has rather narrow wheels and the tyres fitted are Vittoria Competition Rally 21 28" Kevlar 3D Compound. So what size wheels will these be on ?

Thank you for any information !

Regards,

Andy

 

[Zoiders]

Would these be skinny steel framed bikes?

Some saturday scrote probably took the bike to be a 27" "1 '1/4 wheeled bike because it wasnt made from fat aluminium or carbon

700cc is the same thing as 28"

27" 1 1/4" is belive it or not a larger size wheel, but not by much, 700 inner tubes will fit fine

If you have a 700/28" then finding tyres will be easy, 27s are harder to find but you can still find good ones if you know where to look

 

[lastpubrunner]

Yes, they are skinny steel framed bikes.

I'm confused that 27" 1 1/4" is a larger size wheel than 700/28; you state that 700C inner tubes will fit 27" wheels, but will 700 tyres fit 27 inch wheels ?

Both of the bikes have 700/28 tyres, does this mean that I have 700C wheels ?

Thank you for a remarkably prompt reply !!!

 

[Zoiders]

Yes

You could make a 700 fit a 27, but you would have to hang it up and stretch it with something heavy hanging from it

Not worth the effort

The 27 1 1/4" is larger, the 28" marking on 700 tyres is just a bit of sloppy metric conversion

 

[Dave5N]

There'll be a metric/iso number on the tyre, in the format XXX-YY.

That determines the tyre diameter and width.

Tell us that, and there will be plenty of knowledgeable people here who will happily help you consider different options

 

[Zoiders]

There'll be a metric/iso number on the tyre, in the format XXX-YY.

That determines the tyre diameter and width.

Tell us that, and there will be plenty of knowledgeable people here who will happily help you consider different options

That only counts with 26" wheeled bikes, there being 3 different types of 26" tyre

Postie bike style 26", road 26" and MTB 26"

Which are all different metric sizes

700s are all the same diameter, the only limting factor being the rim width, which dictates which width of tyre you can safely use.

 

[mickle]

The gearing limitations are likely to do with the fact that the bike has a screw-on freewheel or low (5/6/7) sprocket numbers.

Few modern shops carry parts stock to suit bikes more than five years old.

if you have Suntour, Maillard, Sachs, Huret, Simplex or Campagnolo parts from that era you're double ****ed. Shi**no. Spit.

 

[Zoiders]

The gearing limitations are likely to do with the fact that the bike has a screw-on freewheel or low (5/6/7) sprocket numbers.

Few modern shops carry parts stock to suit bikes more than five years old.

if you have Suntour, Maillard, Sachs, Huret, Simplex or Campagnolo parts from that era you're double ****ed. Shi**no. Spit.

Availabilty is better than you think

Just dont count on getting Shimano. Campag or Sram bits

After market bits are still on sale for most of the screw on hubs, quality can be iffy though as its kit used on budget bikes using copies of old kit on which the patents have expired

 

[hubgearfreak]

the reason that innertubes are interchangeable, but tyres are not is because the difference is so slight the actual diameter of the rim bead on a '700' is 622mm and for a 27", 630

28s aren't always 622 aashta http://sheldonbrown.com/tire-sizing.html

if you do have 27" rims, don't be fooled by the bike shop into buying new wheels, unless you want to (even assuming that the brake blocks would move down 4mm). the tyres available start here...

http://www.sjscycles.co.uk/category-27-(630)-203.htm