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View Full Version : TUT: how to grind your rim.


soviet911
05-30-2007, 08:54 PM
This is my post from Trials-online.com forum i will be posting other tuts i made also since it seems there no grinding posts on this forum. hopfully will stop people from usking this question again.

welll since alot of pple inclouding my self are confused about how to do a grind and cant decide if they should or not. i decided to make this tut. this is my first grind and if you can add something please pm me and i will add it into the tutorial and obviosly give you credit.
Also before you read all of things i will advise that you dont do this untill you will need the extra stpping power. (might be a good idea to do it once you start doing rear wheel moves and before grinding get a set of trials specific pads CRV's or CRM's are good (v for v-brakeand M for magura.) and once you notice your wheel slips you should do the grind.
P.S At the end of the tutrial you will find all changes and updates done to the tutrial!

:!: WARNING READ THE TUTRIAL 2 TIMES FULLY IF YOU DONT UNDERSTAND IT THEN DO NOT DO IT :!:

Ok so what you wil need
1) angle grinder. ( a 20$ grinder will do the trick or any cheap grinder!)
a 10$ grinder like this will do
http://www.cumminstools.com/browse.cfm/4,643.html (thats how an angle grinder looks)

i used a 4.5 inch grinder but most ppl use 4 inch so its up to you.

2) You need to ha ve a new grinding disk for METAL. it will be a thick disk and will say for metal grinding. Do not use a cutting disk and use a new disk evry 1-2 time you grind a rim, they are only 2$ each so not expansive.

3) preferebly a crappy old rim to test and practice on!

Precedure!
1) Take off the wheel and take of the tire and tube completely (set aside)

2) take a sock or a plastic bag or something to cover up the sprockets.
(srry no pic will get on once i do it again) the idea is not to get aluminum all over your sprockets.

3) Put the rim down on a steady serface (preferably floor) and hold it down with your foot (i hold it with my left foot)

4) turn on the grinder and start Grinding!!! well actualy i will explain and show how to.
so the idea is to turn on the grinder (so it spins) and then lower it down at 45 degree angle onto the rim, once it hits the rim start moving it toward you! depending on how fast you move it the grind will be eather light or harsh. the slower the lighter it will be the faster the harsher it will be also Ottawa_biker suggested that pressing harder will make the grind harsher. just find the grind that you like ( P.S practice it on a test rim) now the hard thing to do is to cover the width of the rim. cuz the rim is wider then the grind so it will make you do it twice to one spot so there will be two or more grind lines parralel to each other depending on how wide your bracking serface is. on your first time it will not be near perfect at all! so dont be dissapointed cuz it will not make your rim any wearse and will improve the bracking. remeber try to keep it constant on both sides so they wear down same. also try doing 4-5 inches at a time (the serface you will grind before stoping and turning the rim) depnding on your rim and your ability, some ppl do 10 inches at a time other do 5 other do 20 inches i did around 5-6 inches a time.

things to keep in mind.
1. its loud
2 its scary.
3 DO NOT STOP AT A POINT ON THE RIM WITH THE GRINDER SPINING! ONCE YOU DONE A GRIND REMOVE IT OF THE RIM OR OTHER WISE IT WILL CHEW UP YOUR RIM. REMEMBER THOSE DISK SPIN AT 10k RPM AND GO THOUGH METAL NO PROBLEM.
4. DO not push the grinder down just let it grind at its own wight depending on the grinder you might need to lift it or push it down.
5. hold the grinder with two hands do not do what i do in the video, that was for a video and was done on my practice rim.

HERE IS THE GIF I MADE. THIS WILL GIVE YOU BASIC IDEA OF HOW TO GRIND. READ WAHT I WROTE ABOVE AND YOU WILL SEE MY MISTAKES RIGHT AWAY the reason for that is i was watching the camera screen and not the grinder so it came out crapy but you still can see the difference between grinded and non grinded parts. and what happens when you grind.

http://i27.photobucket.com/albums/c161/soviet911/HPIM0582.gif
P,S if you think i should slow down the gif tell me. thank you

5) final product PIC BY Genital Apparatus I TAKE NO CRED FOR THIS PIC.
http://i27.photobucket.com/albums/c161/soviet911/grind.jpg


I DO NOT TAKE ANY RESPONSIBILtY FOR WAHT U DO! if you have quastions PM me. please do not post here if its older then a month and PM me. thank you.
if the video dosnt work PM me and i will try to get it up again but i think it will be up all the time. Thank you for reading this!
Thanks for adding in
Ottawa_biker
Last changes
9/20/06-Change from "faster movemnt will get lighter grind and slower harsher grind " to "faster movement will make harsher grind and slower movemnt will make lighter grind" mistake found by Ottawa_biker
SORRY FOR ALL CHANGES AND MY MISTAKES.

soviet911
05-30-2007, 08:57 PM
Oops srry wrong section. can a mod move this to bigginer section. Thanks

isah
05-30-2007, 09:11 PM
mmhh.. i use a cutting disc, and i know a lot of other ppl do, too.. just works better, rills are deeper and cleaner imho but it's more 'dangerous' too, since.. the disc could tear easily

chronic
05-31-2007, 12:02 AM
Good, now post this in kimosabis thread a couple times.

MIKE1968
05-31-2007, 12:04 AM
Oops srry wrong section. can a mod move this to bigginer section. Thanks


Done...one question: what language do you speak?

soviet911
05-31-2007, 12:37 AM
i speack both russian and english.

themunt
05-31-2007, 03:40 AM
I used a vice when grinding my rim.
I put two plates of scrap alloy (you could use wood) as protective plates when tightening the axle of the wheel into the vice. You could also do this in the frame with the tyre and tube off I suppose...
As the grinder came down on the rim, by adjusting the agle of the grinder it made the wheel spin. As a result it took half the time and I achieved a really consistant grind.

Try it.

študent
05-31-2007, 04:49 AM
a 10$ grinder :ugh2:

dkoppric
05-31-2007, 08:34 AM
a 10$ grinder :ugh2:

you like to spend more money on a tool you use every couple of months that will accomplish the same job?

eturt9
05-31-2007, 09:00 AM
I spent $10 on mine. It uses electricity to spin a wheel that grinds stuff.

ThatHonkey
06-07-2007, 02:14 AM
I found I get the best results from the mastercraft metal grinder disk. :coold:

rush
06-07-2007, 05:37 AM
Should I edit this for ease of reading?

soviet911
06-07-2007, 05:24 PM
go ahead. i dont have time right now. just add v1.1 to it so and date or i will do that after words. srry i thought i edited it before.

Youngr51
06-13-2007, 07:56 PM
This is my post from Trials-online.com forum i will be posting other tuts i made also since it seems there no grinding posts on this forum. hopfully will stop people from usking this question again.



MMMMMMMM?ok

Povi
06-22-2007, 06:51 AM
i just did my first grind a few hours ago, one question:
should the rills be deep as the ones in the top picture or a bit thinner? is that a deep grind in the picture?
the grind feels rough but in comparison to some ive felt, maybe not enough..

PsyKotyk
08-03-2007, 08:32 AM
So what's the theory behind grinding a rim? Is it that eventually the standard finish of the rim gets plugged with brake pad and dirt?

I have a large home built metal CNC machine in my basement. I think if I get to needing my rim ground, I'll probably do something more like the slots you see on performance car rotors. Just a whole bunch of narrow, shallow forward angled slots every 1/4 inch... so hopefully the structure isn't compromised too much.

To me it seems that a more uniform pattern would be desirable when you're feathering the brakes. The danger of grinding is if you go too deep in a few spots, the same lever pressure will not be the same stopping power in different areas of the rim = upredictable.

I'm suprised manufacturers aren't offering this standard.

rush
08-03-2007, 10:09 AM
Lols.

Grind is great. Harsh and different depths amost always give standrd perfrmance around the rim.

If youre good enough to use it, you wont notie subtle difference.

dengenerate
08-03-2007, 02:47 PM
i just did a real half assed emergency grind last weekend for a group ride in the rain. i was really just looking for more brakes than the standard nothing i was getting with a wet rim. even the bad grind worked incredibly well. i'm a believer.