Grinding Rims.

[hdmackay]

I recently decided to go to grinds as it's getting to that time of year.

I used a brand new, thin metal cutting disc. I had the grinder at quite a shallow angle for a light grind and it felt nice and sharp, however, after a few days the grind feels quite dead. I was wondering if it was down to grinding technique.

I used the search and found quite alot of topics on grinding and there seems to be two main techniques.

The first one: To keep grinding in the same direction doing about 4" sweeps at a time.

As shown in these rim grinding instructional video. Krisboats Guide . This is what I did when I ground my rim.

The second one: As far as rim grinding videos are concerned this one seems more popular. As shown here:

| Other Guide | And this guide . Which consists of moving the grinder in both directions as you grind round the rim.

So I as wondering if I should try that one instead?

Your opinions on what to do would be much appreciated.

thanks

Edited October 31, 2009 by hdmackay

[Ali C]

I only ever move the grinder in one direction.

What rim have you got? Been riding in the wet or mud? What pads?

[hdmackay]

I only ever move the grinder in one direction.

What rim have you got? Been riding in the wet or mud? What pads?

Oright, so you DON'T do what TNN tell you to do in the vid.

Erm, it's an Echo Urban rim which from what i've heard is one of the best grinding rims out there.

Yeah, been riding in the wet, not mud though.

And I have Heatsink Snowies, which aren't that hard a compound so it can't be the pads doing it.

What do you reckon?

[Dale-Hill]

I do mine back and forward and at like 45 degree angle mine use to last about a month of hard riding (more or less every day) With an urban rim and koxx browns

[Jake.]

Sorry for the interruption... But what is rim grinding? What does it do? How does it help?

[Jake Beach]

Sorry for the interruption... But what is rim grinding? What does it do? How does it help?

http://www.trials-forum.co.uk/wiki/How_to_grind_a_rim

[hdmackay]

I do mine back and forward and at like 45 degree angle mine use to last about a month of hard riding (more or less every day) With an urban rim and koxx browns

Oright, hmm... Seems to be quite even as to what techniques people use.

My grinds seem to be deep enough, but not sharp enough.

i did a light grind and it felt sharp, but now, it doesn't feel sharp but it is still resonably deep if you get me?

[Dale-Hill]

Oright, hmm... Seems to be quite even as to what techniques people use.

My grinds seem to be deep enough, but not sharp enough.

i did a light grind and it felt sharp, but now, it doesn't feel sharp but it is still resonably deep if you get me?

Mine use to do that. Lasted one ride

So i changed the angle and it was much better.

[Canardweb]

I have been trying an awful lot of grinding of method on 6 different bike (all the people of my local club's bikes). Now the best one after 6 months of experimenting:

-Make sure you have a good clean rim (Also some rims hold the grind much better than others: for example DX32 hold the grind very well). If your rim is dirty, clean it with aceton. This is because my method does not remove material but just conditions the rim!

-Then, always leave the tyre on the wheel, never take it away from the wheel or it will put some rubber from the tyre on your rim, this will result on a contaminated grind.

-Start grinding, if you run an HS33, grind the rim the opposite way from when the wheel turns,

if you run Vees, grind the rim the same way the wheel turns.

I don't know why but both these type of brakes perform better depending on the direction you grind your rims...

-Always use a brand new Metal cutting disc, about 2 or 3 mm wide.

-When you grind, never push on the grinder, just let it touch your rim and move your arm around.

-Choose your own angle depending on the depth of the grind you want. As you use a metal cutting disc, be careful not to put it under 30 degrees, or the disc will potentially break (and it's not funny, believe me!).

-Grind all the Rim surface, otherwise, if your wheel is untrue, the pads will touch a part of the rim that is not grinded --> BRAKE FAIL!

-Sand your pads afterwards to remove all the previous stuff that could be on the rims before the grind.

-Take your time when griding, you don't want to damage your rim, and you'll get faster after many griding.

Edited November 1, 2009 by Canardweb

[hdmackay]

I have been trying an awful lot of grinding of method on 6 different bike (all the people of my local club's bikes). Now the best one after 6 months of experimenting:

-Make sure you have a good clean rim (Also some rims hold the grind much better than others: for example DX32 hold the grind very well). If your rim is dirty, clean it with aceton. This is because my method does not remove material but just conditions the rim!

-Then, always leave the tyre on the wheel, never take it away from the wheel or it will put some rubber from the tyre on your rim, this will result on a contaminated grind.

-Start grinding, if you run an HS33, grind the rim the opposite way from when the wheel turns,

if you run Vees, grind the rim the same way the wheel turns.

I don't know why but both these type of brakes perform better depending on the direction you grind your rims...

-Always use a brand new Metal cutting disc, about 2 or 3 mm wide.

-When you grind, never push on the grinder, just let it touch your rim and move your arm around.

-Choose your own angle depending on the depth of the grind you want. As you use a metal cutting disc, be careful not to put it under 30 degrees, or the disc will potentially break (and it's not funny, believe me!).

-Grind all the Rim surface, otherwise, if your wheel is untrue, the pads will touch a part of the rim that is not grinded --> BRAKE FAIL!

-Sand your pads afterwards to remove all the previous stuff that could be on the rims before the grind.

-Take your time when griding, you don't want to damage your rim, and you'll get faster after many griding.

Thank you sooo much for that. I think it's really gonna help.

Just a couple of questions, Quite alot of people say to do both sides clockwise so it holds in both directions, do you find doing both sides anticlockwise (for maggies) is better than that?

And I take it you only grind each side in one direction yes? You don't do the back and forth method?

And how long will a grind like that last you roughly?

[Jake.]

http://www.trials-forum.co.uk/wiki/How_to_grind_a_rim

Thanks! :bow:

[Ali C]

I have been trying an awful lot of grinding of method on 6 different bike (all the people of my local club's bikes). Now the best one after 6 months of experimenting:

-Make sure you have a good clean rim (Also some rims hold the grind much better than others: for example DX32 hold the grind very well). If your rim is dirty, clean it with aceton. This is because my method does not remove material but just conditions the rim!

-Then, always leave the tyre on the wheel, never take it away from the wheel or it will put some rubber from the tyre on your rim, this will result on a contaminated grind.

-Start grinding, if you run an HS33, grind the rim the opposite way from when the wheel turns,

if you run Vees, grind the rim the same way the wheel turns.

I don't know why but both these type of brakes perform better depending on the direction you grind your rims...

-Always use a brand new Metal cutting disc, about 2 or 3 mm wide.

-When you grind, never push on the grinder, just let it touch your rim and move your arm around.

-Choose your own angle depending on the depth of the grind you want. As you use a metal cutting disc, be careful not to put it under 30 degrees, or the disc will potentially break (and it's not funny, believe me!).

-Grind all the Rim surface, otherwise, if your wheel is untrue, the pads will touch a part of the rim that is not grinded --> BRAKE FAIL!

-Sand your pads afterwards to remove all the previous stuff that could be on the rims before the grind.

-Take your time when griding, you don't want to damage your rim, and you'll get faster after many griding.

Good tips, especially leaving the tyre on, so many people take their tyres off, but the release agent companies use to remove the tyres from molds, dirt and general ming will ruin a grind before you even get riding.

[Matt Burrows]

Or you just clean your rim afterwards . I can't stand grinding with the tyre on, it makes it so awkward and harder to put real force into the grinder. I also hate cutting discs for the same reason, you have to be so gentle and the grind is always shallow. I use a NEW metal grinding disc (they go blunt and crap after 1 or 2 grinds) which is much stronger, which means you can put more force behind the grinder. I hold at a 45 degree angle and do 2-3" at a time. Grinding discs are surprisingly strong and you can literally hit the rim with the grinder if you want a really savage grind.

P.S. Always wear eye protection at the very least! If your stupid enough to risk it and not use protection you deserve to go blind!

[Canardweb]

No, the best way to just condition your rim is not to do the back and forth method! This would remove an awful lot of materail and your rim could not take more than 4 or 5 grinds where as just grinding the opposite way your wheel turns (for a maggie) will just clean and recondition your braking surface.

What I mean is: just swing your arms around the opposite way your wheel turns and just let the grinder touch your rim! Then when you go back to re-do the surface, just don't put the grinder on the rim! Remember than the less the grinder touches the rim, the better the rim will hold your grind!

This way you will get a nice sharp grind that will last for a long time! Approximately 3 or 4 weeks depending on how much you ride!

Cleaning your rim after grinding is not a good idea, this will flaten your surface, and it will be like you have a dead grind! (That can be useful if you use CRM pads)

Edited November 2, 2009 by Canardweb

[hdmackay]

Thank you so much guys.

[ogre]

if your part of team tyre removal using alcohol based wipes (medical or screen cleaning) will usually remove the tyre lube

[hdmackay]

Think i'll stick with leaving the tyre on. Thanks for the tip anyway though.