steering stem diameters Loop and Tonti

[lazlokovacs]

anyone know if a drum brake loop and a late tonti (cal vintage) share the same steering stem diameters?

the tonti is mucj longer, but I can't find any info on diameters

bearings and races too?

cheers

[Rick4003]

I believe that the tonti steering stem is 25mm

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[Antietam Classic Cycle]

Both use the same bearing: a 30205 tapered roller bearing, so stem o.d and steering head i.d. are the same obviously.

[Rick4003]

Gregory Bender has the bearing reference on his site. Tonti and loop has the same size bearings.
For tonti:
http://www.thisoldtractor.com/moto_guzzi_tonti_steering_head_bearing_cross-references.html

For loop:
http://www.thisoldtractor.com/moto_guzzi_loopframe_steering_head_bearing_cross-references.html


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[lazlokovacs]

realise now I coulda got my answer from the parts books so double thanks to all!
 

[EldoMike]

Tonti stem is not that much longer than the loop...when I built this I just put a spacer under the bottom bearing...

[Rick4003]

The later tonti 1985-2014? Had a longer steering stem than the pre 1985 models. So it depends on which model year you take.

The early stem is around 170mm long and the later one is around 220mm long. So it is quite a spacer you would have to fit.

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[EldoMike]

The later tonti 1985-2014? Had a longer steering stem than the pre 1985 models. So it depends on which model year you take.

The early stem is around 170mm long and the later one is around 220mm long. So it is quite a spacer you would have to fit.

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Yeah, should have noted that the front end came from a 850T

[guzzisteve]

It started getting longer on 83 models in US, my LM3 neck is more than my sold 80 SP. The Cali 2 is alot longer neck. The Sport 1100 front end I put on my LM3 needed 230 thousands spacer.

[Kiwi_Roy]

Tonti stem is not that much longer than the loop...when I built this I just put a spacer under the bottom bearing...

How did the bike handle good I'm thinking but some of the character of an old loop would be lost knowing it would stop.
I just have the twin leading shoes on my Eldo, I always have to be thinking about an exit route LOL

Sorry, what's the front end off?

[mtiberio]

It started getting longer on 83 models in US, my LM3 neck is more than my sold 80 SP. The Cali 2 is alot longer neck. The Sport 1100 front end I put on my LM3 needed 230 thousands spacer.

My 83 lemans 3 had the same length steering head as my 75 Convert.

[ccoli]

Bearings  may be the same but, diameter where it fits in the triple tree differs I believe. I am looking for the same info in order to install an EV tree on a loop frame.
Frank ? From the Chicago area has done this by pressing the older stem into the new lower tree. He says there is a bushing the correct size available from McMaster Carr.
The other option I'm considering is to cut the EV stem down to the shorter length and weld it between bearing lands.
I am have not taken mine apart and do not own micrometers, only a veneer caliper, so measurements are could only be approximated.

[guzzisteve]

My 83 lemans 3 had the same length steering head as my 75 Convert.

I may have had a bad measurement Mike, this was before I had precise tools on the farm. Goes to show you never stop learning.

[mtiberio]

I may have had a bad measurement Mike, this was before I had precise tools on the farm. Goes to show you never stop learning.

Well, if you are talking the difference being the width of a washer, maybe, but the Lemans 3 def did not have the loooong Lemans 4 steering head.

The only reason I know this is because in 1985(?) I was at summit point to see Dr John and his Lemans IV run an AMA endurance race. He had a rare DNF. as it is I left the track shortly after they did. It seems traffic on summit point (v curvy) road was too slow for me. little did I know that dr johns van was at the front of the line of cars. I made an attempt to pass the whole lot, and didn't make the kink at the end of the straight. Right in front of dr john and his crew and riders, I went blasting past, threw the bike over, dug in some hard parts, and crashed. I destroyed the forks, and broke my wrist. They were all very impressed with how far I got the bike over when we had a laugh over it years later. Since I wanted to ride, I bought a convert (left wrist broken) and rode it while I collected parts to fix the lemans. At various times during the repair (of the bike and me), I had a Convert, a Convert with clipons, a Lemans with a windjammer, and after all those frankenbikes, finally 2 "normal" bikes. Lemans IV's definitely had a tall steer head, but the Lemans III was standard gen 1 Tonti (geometry only, had brake bracket, breather in frame, ok so it was gen 3). The difference on the Lemans III from earlier tontis is, it had a longer than normal swingarm.

As far as never stop learning, I was just called an idiot in the fuel injection thread, so LOL.  8^))

[Antietam Classic Cycle]

Well, if you are talking the difference being the width of a washer, maybe, but the Lemans 3 def did not have the loooong Lemans 4 steering head.

The only reason I know this is because in 1985(?) I was at summit point to see Dr John and his Lemans IV run an AMA endurance race. He had a rare DNF. as it is I left the track shortly after they did. It seems traffic on summit point (v curvy) road was too slow for me. little did I know that dr johns van was at the front of the line of cars. I made an attempt to pass the whole lot, and didn't make the kink at the end of the straight. Right in front of dr john and his crew and riders, I went blasting past, threw the bike over, dug in some hard parts, and crashed. I destroyed the forks, and broke my wrist. They were all very impressed with how far I got the bike over when we had a laugh over it years later. Since I wanted to ride, I bought a convert (left wrist broken) and rode it while I collected parts to fix the lemans. At various times during the repair (of the bike and me), I had a Convert, a Convert with clipons, a Lemans with a windjammer, and after all those frankenbikes, finally 2 "normal" bikes. Lemans IV's definitely had a tall steer head, but the Lemans III was standard gen 1 Tonti (geometry only, had brake bracket, breather in frame, ok so it was gen 3). The difference on the Lemans III from earlier tontis is, it had a longer than normal swingarm.

As far as never stop learning, I was just called an idiot in the fuel injection thread, so LOL.  8^))

I remember that day well - Sept. '85. I gave you a ride to Jefferson Memorial in my Bertone X1/9.