Ducati Monster Forum

Moto Board => Tech => Topic started by: teddy037.2 on May 01, 2009, 07:16:34 PM

Title: Al swingarm w/4.5" wheel
Post by: teddy037.2 on May 01, 2009, 07:16:34 PM
so I just grabbed up an Al arm, and from what I gather, it's really not made for the 4.5" wheel.

is there any easy way to calculate a spacer to make up for it?  difference in width between inside walls of the Al vs steel arms?

or is this one of those "wait n'see" things?


I ask this because I NEED a new rear tire this month, or I won't pass safety.  if I gotta buy a 5.5, I'll just get rubber for that and mount it. somehow I don't see the point to buying new rubber for a wheel that most likely nobody will ever need.

the al arm is not here yet, so I can't do much of anything until it gets here


oh, um... '05 M620...
Title: Re: Al swingarm w/4.5" wheel
Post by: DarkMonster620 on May 01, 2009, 07:41:31 PM
Quote from: teddy037.2 on May 01, 2009, 07:16:34 PM
so I just grabbed up an Al arm, and from what I gather, it's really not made for the 4.5" wheel.

is there any easy way to calculate a spacer to make up for it?  difference in width between inside walls of the Al vs steel arms?

or is this one of those "wait n'see" things?


I ask this because I NEED a new rear tire this month, or I won't pass safety.  if I gotta buy a 5.5, I'll just get rubber for that and mount it. somehow I don't see the point to buying new rubber for a wheel that most likely nobody will ever need.

the al arm is not here yet, so I can't do much of anything until it gets here


oh, um... '05 M620...

Hey teddy037.2,

I've been wanting to ask a long long time ago...

When I got my bike, got the tons of catalogs with it, Alu swingarm with Ohlins shockk, carbon hugger{from DP], ProTwins in UK,show two different types of ALu swingarms, could you or anyone,explaing which one offers what better in comparassion to the other?
I'm really dumbfounded, in this subject...
Title: Re: Al swingarm w/4.5" wheel
Post by: Speeddog on May 02, 2009, 08:15:40 AM
AFAIK, the only difference is that the chain wear guard is set up for the wide wheel, so it'll be a good bit outboard from where your chain is on a 620.
Title: Re: Al swingarm w/4.5" wheel
Post by: teddy037.2 on May 02, 2009, 10:47:49 AM
Al is lighter than steel, which makes it better

just like how CF is lighter than plastic, which makes it better

;)

I had been thinking about swapping the arm for along time, and one just came along at a good price, so... it'd be cheaper for me to make the 4.5 work, so hopefully that'll be the case.

well, more grip is always nice, but it's not like I can ride the shit out of my bike in stock form, so whatever  :D
Title: Re: Al swingarm w/4.5" wheel
Post by: BastrdHK on May 02, 2009, 12:55:25 PM
I have bought an '04 m1000(not S2R) aluminum swinger and 5.5" wheel that will not fit my '01 m900 b/c I have the hoop style suspension and smaller rear axle.

I will sell you the wheel if you need it.  Let me know.

Title: Re: Al swingarm w/4.5" wheel
Post by: teddy037.2 on May 02, 2009, 02:30:03 PM
Quote from: BastrdHK on May 02, 2009, 12:55:25 PM
I have bought an '04 m1000(not S2R) aluminum swinger and 5.5" wheel that will not fit my '01 m900 b/c I have the hoop style suspension and smaller rear axle.

I will sell you the wheel if you need it.  Let me know.



groovy, thanks! I'll keep that in mind  [thumbsup]
Title: Re: Al swingarm w/4.5" wheel
Post by: teddy037.2 on May 03, 2009, 11:58:47 AM
one more question on the swap... (just mostly for confirmation) but the rear brake/speedo setup, axle, are they all swappable?
Title: Re: Al swingarm w/4.5" wheel
Post by: BastrdHK on May 03, 2009, 01:03:19 PM
I think all your parts are interchangeable(the axle is 25mm iirc)  the major issue you are going to have if you use the 4.5" wheel is getting it spaced correctly so that your rear brake assembly/rotor/bracket/chain/sprockets are aligned correctly.  If I wanted to use that wheel on my bike I would have to put a 1" spacer on the rear brake side between the swingarm and rear brake bracket and extend the tab or tap it and extend with a bolt to keep the rear brake assembly from rotating forward during braking.  This is the only way I could keep my chain/sprockets in line, but would cause a tracking issue since the wheel would be off center.

Sacrificing chain/sprocket alignment will cause uneven wear at the least.  Misalignment by as little as 1/8" results in 3-5% power loss.

It sounds like performance gain is what your going for, and honestly, I think the added weight of a 5.5" wheel/tire vs. grip gained will not help your particular bike regardless of the aforementioned concerns.  It sounds like an alum. swinger for a 4.5" wheel is what you should look for.  Do they make those?

I have an aluminum swingarm, but that SOB is still heavy!  I haven't weighed and compared my steel swingarm, but after carrying it around and the modifications involved to make the alum. work I shied away from it.  The alum swingarm is only half aluminum anyway.  The shock mounts, pivot arms, and bracing are a heavier metal.   
Title: Re: Al swingarm w/4.5" wheel
Post by: Duck-Stew on May 03, 2009, 01:10:53 PM
2000 - 2001 M900 Dark's were available with a steel arm and a 5.5" wheel.  The difference in width is measured where the tire mounts to the wheel and not the hub width.

You shouldn't have an issue with a 4.5" wheel and an aluminum swingarm.
Title: Re: Al swingarm w/4.5" wheel
Post by: teddy037.2 on May 03, 2009, 05:49:23 PM
thanks for the info, guys!

[thumbsup]

hopefully this swap goes well... if not, well, it's to be expected  [laugh] this pregnant dog fights me tooth and nail over any change from stock
Title: Re: Al swingarm w/4.5" wheel
Post by: caboteria on May 03, 2009, 07:16:12 PM
2002 M750S i.e. has an aluminum swingarm and a 4.5" rear, so you should be able to find what you need.
Title: Re: Al swingarm w/4.5" wheel
Post by: teddy037.2 on May 04, 2009, 09:06:38 AM
Quote from: caboteria on May 03, 2009, 07:16:12 PM
2002 M750S i.e. has an aluminum swingarm and a 4.5" rear, so you should be able to find what you need.


groovy

so Mac900 might be right after all lol