Need to replace old tyres, but not sure of size.

[Tedcase]

Hi all, This is my first post.

Ive been working on rebuilding an old french racing bike for a while now, and am finally looking at replacing the old worn out tyres.

I found some on e-bay that look ok, and are cheap enough (i am on a VERY tight budget).

Unfortunatley, Im not certain what size i need to be looking for, as the measurements on the old ones are not all that clear.

The tyres i do have are Michelin and have this written on the sides;

(28 x 1 5/8 x 1 1/4 x 1 1/8) 32-622 (700 C Course)

I have no idea what all this means.

In your expert opinion then, do you think these tyres;
http://cgi.ebay.co.uk/Schwalbe-blizzard-Sport-Road-Tyres-PAIR-700x23c-NEW-/130440781989?pt=UK_sportsleisure_cycling_bikeparts_SR&var=&hash=item641e82752a

will fit?

Sorry if this is a stupid question.

 

[Scotty_Dog]

Read this regarding tire sizes:
http://sheldonbrown.com/tire-sizing.html#width

The first set of numbers you listed, 28 x 1-5/8 x 1-1/4 x 1-1/8, represents an older naming system for tire sizes in inches. The second set of numbers, 32-622, is the tire width (32mm) and inside diameter (622mm). The third number, 700, is the approximate outside diameter of the tire (700mm).

Modern road bike tires are typically listed in millimeters as outside diameter x width, or in the case of your old tires 700 x 32.

The 700 x 23 replacement tires would probably fit, but it's really determined by the inner rim width. Measure your inner rim width and use the chart at the bottom of the page I linked above, or tell us your measurement for more recommendations.

 

[Tedcase]

wow, Thanks for the prompt reply!

I had another look at the wheels themselves, the only markings i can make out on them are "Lyotard S C" Im guessing Lyotard is the brand name. I also took a rough measurement and i think the width of the wheel itself is 2 cm.

I dunno if that makes it any clearer. Its odd that i need all these old figues just to find out if it fits Size 700 x 23c. I guess in future i should just avoid buying bikes older than myself.

 

[daveryanwyoming]

Your old tires are 700x32c. You could replace them with the same or something a bit narrower like 700x28 or even 700x25 tires. Your rims will very likely take 700x23 tires if the outside measurement is roughly 20mm as you mentioned but those are going to seem really, really narrow compared to what you have now. If it's a road bike you'll ride fast then 23c tires are pretty common but a lot of folks prefer a bit more tire width for additional comfort and often a bit less chance of flats with some of the durable slightly larger tires on the market.

The really important measurement is 622 (700c) once you get past that the specific width is more flexible. I've run 21c all the way up to 35c cyclocross tires on the same 700c rims (21mm outer rim width, 19mm inner width) with no issues at either end of the spectrum.

-Dave

 

[Tedcase]

Thanks for the input Dave, some really good info here. whether or not i get my bike upgraded, at least i know im learning something!

Did you get chance to look at the e-bay link?

I guess it all really boils down to whether or not the tyres will fit. I dont mind running on slightly narrower tyres, my main concern right now is the fact that the ones i have on now are about 30 years old and are going to split at any moment.

 

[Tedcase]

Oh, dunno if this helps or not, but here is an old picture of the bike in question;



Ive done quite a bit of work on it sine this pic was taken, but the wheels and tres are still there.

 

[alfeng]

Originally Posted by Tedcase .


I guess it all really boils down to whether or not the tyres will fit. I dont mind running on slightly narrower tyres, my main concern right now is the fact that the ones i have on now are about 30 years old and are going to split at any moment.

While any 700c tyre will have the correct inner circumference to fit on the rim, I think that if you think about it AND apply [COLOR= #008000]simple geometry[/COLOR] that you will find that a 700x23 tyre mounted in your current rims will result in a very low profile tyre -- very gangsta ...

• that is, [COLOR= #008000]if you were lengthen the base of a triangle, the height would be lower, and vice-versa[/COLOR].

I reckon your rims are in the 622-[COLOR= #ff0000]17[/COLOR] (or, possibly 622-19) range where the [COLOR= #ff0000]second number[/COLOR] is the bead-to-bead measurement ([COLOR= #808080]i.e., the gap between the beads[/COLOR]).

Not quite arbitrarily estimated, but for the best results a 622-17 rim probably should not have a tyre smaller than 700x25 ... 700x28 would be better ...

A 622-19 rim probably shouldn't have a tyre smaller than 700x28 ...

et cetera.

So, IMO, you do NOT want the 700x23 tyres which you previously indicated.

BTW. 700x28 & 700x32 tyres usually use the same size inner tube, but not always. If you were to buy 700x25-or-smaller tyres then you would probably need new inner tubes, too.

 

[Tedcase]

Thanks for the help! all much appreciate. Ill have another look about for some 700x32 tyres then.

 

[Tedcase]

Hi guys, I went ahead and bought them. They fit perfectly and look awesome. Thanks alot for all the help. I know it was a stupid question to begin with but combining my very limited funds and even more limited cycling knowledge I had to be careful.