Le Mans 1 wheels

[Jihelle]

I've just introduced myself, so now is my question:
I have a 1978 Le Mans 1 that I bought a few years back with spoke wheels and front brake rotors almost certainly from a T3.
I wish to revert that bike to the original cast wheels and drilled rotors.
I bought a set of second-hand cast wheels with the "kink" in the spokes (not the straight spoke as seen in the "Lester" type wheels) and was told by the seller that they would fit LM1/LM2/LM3 and SP models.
I am now in the process of fitting them to the bike but I still have to buy a (costly) set of new LM1 rotors from Gutsibits or Stein-Dinse. Before doing this, I would like to make sure that these wheels were the same for LM1/LM2/LM3 (all the research have done tend to prove they are) but I have a nagging doubt that there may be some difference with SP wheels, these being wider at the center and therefore unable to accommodate LM1 disc rotors. If so was the case, is there anyway to differentiate LM1/LM2/LM3 wheels and SP wheels ?  I found some reference in the forum to this topic but they seem to refer to G5 cast wheels.
Thanks for any wisdom you would share with me on the topic.

[Arizona Wayne]

If you had a Guzziology book written by Mr. Richardson in Seattle, Wa. you could probably find this out.  I have a CX100, same as a LM II but with a SP motor instead of the 850 motor.  I know the LM1 & LM III have narrower front forks than my CX does, but don't know if this  matters.  I suspect this doesn't matter.   Maybe just the axle does matter for the mag rims they all came which look the same to me.  In fact I know a SP mag of the same era is the same rim since I have 1 I used to have on my CX when its original mag got bent by a rock.

As far as performance you are better off with wire rims as the mag rims of that era are heavy compared to spoke rims.  The brake rotors of both rim sizes are not interchangeable because they have different bolt patterns (5 vs. 6). 

[Jihelle]

Well, I had Guzziology and I had a CX100 also some 10 years ago.  But I very stupidly sold the CX100 to some nice gentleman from Arkansas when I left the U.S at the time and gave him the book in a random act of kindness. I guess it's time to buy it again. I loved the CX100 but I prefer the 850 engine so I don't regret it too much. The CX100 was never produced in Europe and I would have had to go through a lenghty and costly homologation process to import it.
I am afraid that what the problem is. The fork of the LM1 is narrower than the SP's but the disc rotors appear to be the same on both models. So I guess what gives are the wheels though they look pretty much the same. Steine-Dinse lists the same wheels for LM1/2/3 (not available for sale anymore) but a different model for the SP though it's not totally clear in their diagrams database
You may be right. The best solution is maybe to leave it as is. Spoke wheels look better anyway. Rather than investing in old "rotors", I could be better off investing in a set of floating new brakes...but I am a sucker for the "original" look.

[Arizona Wayne]

Well, I had Guzziology and I had a CX100 also some 10 years ago.  But I very stupidly sold the CX100 to some nice gentleman from Arkansas when I left the U.S at the time and gave him the book in a random act of kindness. I guess it's time to buy it again. I loved the CX100 but I prefer the 850 engine so I don't regret it too much. The CX100 was never produced in Europe and I would have had to go through a lenghty and costly homologation process to import it.
I am afraid that's what the problem is. The fork of the LM1 is narrower than the SP's but the disc rotors appear to be the same on both models. So I guess what gives are the wheels though they look pretty much the same. Steine-Dinse lists the same wheels for LM1/2/3 (not available for sale anymore) but a different model for the SP though it's not totally clear in their diagrams database
You may be right. The best solution is maybe to leave it as is. Spoke wheels look better anyway. Rather than investing in old "rotors", I could be better off investing in a set of floating new brakes...but I am a sucker for the "original" look.

The CX was made only for the  US because the LM II couldn't meet the  EPA  pollution requirements of the time(`79-`81`), tho the LM III was sold  in Calif. later. Canada did get the LM II.

[guzzista]

Pretty simple. The spacing on the narrow wheels for the  deep  brake rotors dish is 36mm. A 60 mm bolt will fit through both rotors and leave somewhere close to 10mm to fit the nut. No matter which rotors you have ( deep or narrow), try this and you will know. To my knowledge the hub width is the same  on LM1 and SP bent spoke wheels, but spacers were added for SP, LM2 and CX. I still have those spacers left over from when my CX went to a Marzocchi Strada ( narrow) fork conversion and the spacers were removed. 

[Gino]

My mk1 lemans has a small kink in the front wheel (since I bought it over 20 years ago) I bought a front wheel a while back and it didn't fit, it did though fit my pals Spada. Just yesterday I bought a pair of wheels allegedly for a mk1/2 lemans, they were cheap so I haven't checked if they fit yet

[guzzibob]

 My understanding is that the SP and Convert cast wheels in fact are wider at the hub. In effect on these models the spacer is built into the wheel casting I know this because I converted my T3 from spoke to cast wheels and needed the wider casting from an SP  so as not to need spacers and that was the case on the front wheel. That made it an easy direct bolt on. The narrower (at the hub) cast wheels from the LM would have required a spacer to fit on my T3. So for the LM you need the narrower hubbed wheel.

[Arizona Wayne]

My understanding is that the SP and Convert cast wheels in fact are wider at the hub. In effect on these models the spacer is built into the wheel casting I know this because I converted my T3 from spoke to cast wheels and needed the wider casting from an SP  so as not to need spacers and that was the case on the front wheel. That made it an easy direct bolt on. The narrower (at the hub) cast wheels from the LM would have required a spacer to fit on my T3. So for the LM you need the narrower hubbed wheel.

I acquired a `77 Guzzi Convert. last summer with wire wheels.  Put a `81 CX100/SP mag on the back and found that the wire wheel setup had a spacer on the rear axle to match the width of my CX mag rim.  Everything else was the same dimension wise. 

[mtiberio]

Lemans 1 and Lemans 3 have 180mm front ends. (center to center dimension of fork tubes).
Lemans 2 and SP have 195mm front ends.

Some of the bikes with 195mm front ends, had wheels with no spacers between the rotors and the wheel. That is the wheel was cast and machined "wider".
Some of the bikes with 195mm front ends obviously used the wheels from the 180mm front ends, and had 7.5mm spacers on each side to move the rotors out from the narrower hub.

ymmv

[Jihelle]

Well, after further investigation, cast wheels for Le Mans 1 and Le Mans 2 are indeed different. Wheels for LM1 have a "3001" number engraved in the cast, LM2 have  "3002".
Dunno about MK3, SP and other Tonti's with cast wheels. LM2 also have floating discs and LM1 don't. The "3002" wheels are indeed larger at the hub and the LM1 fork is narrower... So, to cut a long story short,  my "3002" wheels can't fit on my LM1 with the OEM rotors unless Guzziology (now on its way) offers some kind of solution...

[mar54]

Lemans 1,2,3 have the same front brake rotor, it is larger offset than SP and similar model brake rotors.
Lemans 1,2,3 mounts the same front cast whell, it is like to SP and similar model but with closer hub.
Lemans 1 and 3 have a 180 fork, Lemans 2, PS and similar model have a 195 fork
Lemans 2 Mount 8mm. spacers with front brake rotors
Convert mk1 (spoke whells) have front brake rotor like Lemans serie, but with SP and similar model offset
Lemans 1,2,3, SP and similar model have the same rear cast whell