When to replace rims?

[I893469365902345609348566]

My rims might need replacing soon... the wear indication line is surrounded by deep rim brake erosion lines, and the rims are looking a bit concave.

If I put cut up a spoke and hold two spoke sections against the concave areas at either side of the rim, and measure their combined thickness using a digital micrometer, I can work out rim thickness by subtracting spoke thicknesses. But how thin is too thin?

 

[Sturmey]

I keep using rim until wear indication line disappears entirely or rim wall start to splay outwards sometimes causing a pulsing that can be felt in the v brakes. Attached below old article with same idea as yourself but mainly refers to rims without wear indicator.

 

[Bikes4two]

What you need is an iwanson guage - ebay less than a tenner (10 GBP) - then google for bicycle minimum rim thickness to which you'll get various answers - a typical range of acceptable minimum thickness is 0.7mm to 1.0mm.

Definitely worth getting one - if like me you've been out on a ride when the rim starts to give (often indicated by suddenly getting brake block rub), you start to wonder where the nearest train station is.

Now when I've got the tyre off at home and the rim has done a few thousands of miles, out comes the guage - a quick measure-up takes but a minute or two which for peace of mind is worth while doing

 

[I893469365902345609348566]

I keep using rim until wear indication line disappears entirely or rim wall start to splay outwards sometimes causing a pulsing that can be felt in the v brakes. Attached below old article with same idea as yourself but mainly refers to rims without wear indicator.

Thank you that's very interesting and useful information. His idea of making a rim guage using a spoke is a much better idea.

 

[I893469365902345609348566]

What you need is an iwanson guage - ebay less than a tenner (10 GBP) - then google for bicycle minimum rim thickness to which you'll get various answers - a typical range of acceptable minimum thickness is 0.7mm to 1.0mm.

Definitely worth getting one - if like me you've been out on a ride when the rim starts to give (often indicated by suddenly getting brake block rub), you start to wonder where the nearest train station is.

Now when I've got the tyre off at home and the rim has done a few thousands of miles, out comes the guage - a quick measure-up takes but a minute or two which for peace of mind is worth while doing
View attachment 48795

I'll buy one of those. Changing rims at 1mm seems wise. Thank you.

 

[AndyBike]

Keep in mind the pressure you have in the tyre. Higher pressure and reduced wall thickness = more chance of the rim failing, and you being pitched chin first into the tarmac.

As most here will be tarmac riders, tyre pressures will be higher as per norm.

Of course if you go disc, theres no need to replace rims unless they become damaged in other ways.

 

[Plas man]

having recently replaced a front wheel (rear hub drive) , on checking price was to find that front hub dynamo wheels came cheaper , 26” was £26 - eBay

 

[pschamberger]

If the rims can't hold air, or cause braking and handling problems, they need to be replaced. Cause worn or damaged rims can cause sudden deflation even if the leak seems slow or the crack appears small.

 

[georgehenry]

Back when I was acoustic mountain biking in sandy surrey with powerful rim brakes I was changing the rims every year! Then a friend sold me cheaply some Mavic ceramic rims that refused to wear out until I stopped riding that bike. It was a very nice Marin bike but I bought the last year of rim brakes. However they were very powerful rim brakes, which probably contributed to my rim wear.

 

[I893469365902345609348566]

I've never heard of ceramic rims, which sound like a good idea and also quite exotic. I can't see any available to buy. Did disc brakes made them obsolete?

 

[georgehenry]

Yes. Might be a bit overkill on your bike, but they would probably never wear out.

 

[I893469365902345609348566]

Yes. Might be a bit overkill on your bike, but they would probably never wear out.

Were your rims metal with a ceramic coating on the braking surface? Rims which never wear out is not overkill! It's a thoroughly sensible feature. Can't see any ceramic rims on Aliexpress at all, but I did spot some carbon fibre rims for v-brakes with a basalt rim surface treatment. About £120 each. I doubt that basalt is everlasting, when it's dust glued onto carbon fibre.

 

[I893469365902345609348566]

Of course if you go disc, theres no need to replace rims unless they become damaged in other ways.

I guess there's not much need to true wheels when your bike has disc brakes?

I may attempt converting to disc, if get the right hubs with disc connection points and using a conversion kit, building my own wheels, or get my bike shop to build after supplying all the parts.

 

[AndyBike]

I may attempt converting to disc, if get the right hubs with disc connection points and using a conversion kit, building my own wheels, or get my bike shop to build after supplying all the parts.

Ive some new Hope calipers if you are interested - though you'd need to buy levers for them. E4 for the front (a 4 pot) and X2 for the rear(a 2 pot)
Luscious purple

What size of wheel have you on the bike ?.

 

[georgehenry]

Now you ask, I am not sure. I expect they are a coating. The wear rate was startlingly less than the previous rims. Although I don't know, the advent of hydraulic disc brakes that appeared on Marin's next years model, and became prevalent would have meant rims no longer had to put up with brakes rubbing on them. This would have been particularly apparent on mountain bikes used off road in mud and rain making the rims have to deal with the equivalent of grinding paste and as I found leading to your rims wearing out very quickly. Ceramic rims were always expensive and the guy who sold me the pair I put on my Marin had them hanging in his garage and sold them to me cheaply as the market for them had disappeared.

 

[I893469365902345609348566]

Ive some new Hope calipers if you are interested - though you'd need to buy levers for them. E4 for the front (a 4 pot) and X2 for the rear(a 2 pot)
Luscious purple

What size of wheel have you on the bike ?.

As I tell all the girls: 20 inches! Thank you for your kind offer, Hope do appear to make some fantastically high quality products. I expect you'd be able to sell them for quite a lot on ebay. Being a bargain basement sort of cyclist, my plan is to try a rear wheel disc conversion as cheaply as possible first, and if it all works well and better than my V-brakes, improve it with better parts.

 

[georgehenry]

Looks quite therapeutic, rain is forecast tomorrow!