LeMans 1000 16” Front Wheel

[Kane]

Looking around for Tonti frame bikes I have found a LeMans 1000, 1986 model with the stock 16” front wheel. My impression is that the 16” wheel is considered undesirable, and I have heard that this model may also have smaller brakes or rotors (?). How much of an issue is the smaller wheel and brakes on these models? I’m also wondering if the frame geometry is different on the 16” wheel bikes compared to the bikes with the conventional 18” wheel. How hard is it, and how well does it work, to convert these bikes to 18” front wheels?

I have read that people don’t like the handling, that some feel they are a little unstable because of the 16”, and that putting a 16” on the LM was more of a marketing move than an engineering move. But also that Dr. John had much success racing these, but it would be a road bike for me, not a racing bike.

For getting into a carbed Tonti Guzzi via the ‘86 LM1000, is the 16” wheel and smaller brakes (if that’s the case) a deal-breaker? It would be great to hear from those of you who have experience on these.

Hope everyone is well! Thank you

[gstallons]

Ride it w/the 16 in. wheel for one year , then decide what you want to do .

[Pressureangle]

I bought my '85 LM with the 16" stock wheel, didn't like it at all. Poor feedback, insecure, twitchy-while-disconnected feel. It had Metzeler lazer on the front.
I found an 18" front, which I ran for about 30,000 miles. It was dead stable with any tire I put on it. I'm in S. Florida, so there was never any way to know how it cornered.
Fast forward ten years, I completely rebuilt the bike from the crankshaft up to pass along to my son. After some consideration, I installed the 16" front with Continentals; at the same time I installed Works Performance shocks, 1/2" longer than the stock Konis; Upgraded fork springs and FAC dampers. After some spirited if limited local riding, I ended with the forks out of the top triple clamp about an inch. These are the steel clamps, I have no way to know if they're 'original' or 'kit' trees, and don't know the exact difference. Ultimately, the thing was a lumber wagon with the 18", perfect for fast straight riding but with proper setup the 16" is perfectly stable with good feedback and confidence, while being enormously easier to turn in all circumstances.
It's possible that the thing just really hated the Metzeler front it came with, but I never tried something else before the swap.

So there's no definitive answer, but that there is no inherent problem with the 16" front. You just have to find what it likes.

[Lucky Phil]

1 hour ago, Pressureangle said:

I bought my '85 LM with the 16" stock wheel, didn't like it at all. Poor feedback, insecure, twitchy-while-disconnected feel. It had Metzeler lazer on the front.
I found an 18" front, which I ran for about 30,000 miles. It was dead stable with any tire I put on it. I'm in S. Florida, so there was never any way to know how it cornered.
Fast forward ten years, I completely rebuilt the bike from the crankshaft up to pass along to my son. After some consideration, I installed the 16" front with Continentals; at the same time I installed Works Performance shocks, 1/2" longer than the stock Konis; Upgraded fork springs and FAC dampers. After some spirited if limited local riding, I ended with the forks out of the top triple clamp about an inch. These are the steel clamps, I have no way to know if they're 'original' or 'kit' trees, and don't know the exact difference. Ultimately, the thing was a lumber wagon with the 18", perfect for fast straight riding but with proper setup the 16" is perfectly stable with good feedback and confidence, while being enormously easier to turn in all circumstances.
It's possible that the thing just really hated the Metzeler front it came with, but I never tried something else before the swap.

So there's no definitive answer, but that there is no inherent problem with the 16" front. You just have to find what it likes.

Look up the rake and trail specks for the original bike and then measure yours with the steel triples. I didn't know there was a "kit" for them. The difference will almost certainly be in the trail which will be changed by the offset between the steering stem centre and the fork centres. Easy to measure with a short straight edge and a tape measure across the top triple clamp if you have an original bike to compare to if not its a ground measurement.Sometimes though there is a curve ball from those days where the upper and lower triples have a different offset, I think my RC-30 was like this.

I had two friends back in the 80's that both had 16" wheeled Guzzies both ex racers. One had a LM04 which he bought in Mandello when we were over there touring together and the other a T5. As I said both were ex racers and one was an "A" grader here that raced in the Castrol 6 hour a few times.

Both had no complaints about the 16 inch front wheel other than the the lack of tyre choices after a while. I seem to recall at least one of them on the LM used Lazer tyres. 

I also had a factory Ducati TT2 back at that time I used on the track and it had a 16" front wheel and despite all the Ducatisti saying it was bad I never had an issue with it. The bike I mechaniced on in the IOM in 86 was also a factory 16" wheeled TT2 and it did practice and 2 races and then went on to do the rest of the F2 season in Europe and was never an issue on the roads or closed circuits either. 

Personally I think the 16" front just went out of fashion when race bikes stopped using them and people tried to justify it. Also Ducati riders especially and probably most others were used to slow steering bikes nothing like we have today and weren't used to the quicker more agile steering the 16 gave. Ducatis steered like a truck in the early 80's and Ducatisti thought that was great handling when in fact it was just a lot of stability. I remember my first ride on my RC-30 Honda over a fast piece of country road after years of riding the same road on my Hailwood Mille. I was just gobsmacked at how brilliant the Honda handling steering and suspension was. 

Ciao

[docc]

12 minutes ago, Lucky Phil said:

Sometimes though there is a curve ball from those days where the upper and lower triples have a different offset, I think my RC-30 was like this.

Some reliable sources that the very earliest V11 Sport had this very "curve ball" but was abandoned early on.  Perhaps part of the impression of how badly the V11 sport handled (as introduced).  There is a thread trying to get owners of early V11 to verify their triple tree part numbers, but it got no real traction.

Also, apparently, there is an early service bulletin addressing this "offset triple clamp" issue (on the V11 sport, but I've never seen the source document. (Unless one of you might have it?????)

 

[Lucky Phil]

7 minutes ago, docc said:

Some reliable sources that the very earliest V11 Sport had this very "curve ball" but was abandoned early on.  Perhaps part of the impression of how badly the V11 sport handled (as introduced).  There is a thread trying to get owners of early V11 to verify their triple tree part numbers, but it got no real traction.

Also, apparently, there is an early service bulletin addressing this "offset triple clamp" issue (on the V11 sport, but I've never seen the source document. (Unless one of you might have it?????)

 

All new info to me docc, but thanks. It was a "thing" back in the 80's and I think my Bimota DB1 also had this. It came with 16 inch wheels front and back but i had friends that raced one in the Aus Superbike series and I converted mine over to 5x17 rear and a 3 and 1/4 x 17 front Campagnolos and ran a cut slick on the rear for the street. Arrr, youth a time when I used to hand cut my own tyres and think nothing of doing stuff like this. 

Ciao

[docc]

1 hour ago, Lucky Phil said:

All new info to me docc, but thanks. It was a "thing" back in the 80's and I think my Bimota DB1 also had this. It came with 16 inch wheels front and back but i had friends that raced one in the Aus Superbike series and I converted mine over to 5x17 rear and a 3 and 1/4 x 17 front Campagnolos and ran a cut slick on the rear for the street. Arrr, youth a time when I used to hand cut my own tyres and think nothing of doing stuff like this. 

Ciao

I'll have to go back to Greg Field's excellent Moto Guzzi Big Twins, but I seem to recall Dr. John Wittner saying the 16" front was one of those "modes of the moment." (Love that phrase.)

Apologies for the segue, but here is the thread trying to divine the history of the early V11 "geometry changes" . . .

 

[Lucky Phil]

2 hours ago, docc said:

I'll have to go back to Greg Field's excellent Moto Guzzi Big Twins, but I seem to recall Dr. John Wittner saying the 16" front was one of those "modes of the moment." (Love that phrase.)

Apologies for the segue, but here is the thread trying to divine the history of the early V11 "geometry changes" . . .

 

Info there docc. Looks like my bike is the twitchiest of them all:)

Ciao 

[po18guy]

The 1992-1999 Honda CBR900RR had a 16" front with a 17" rear. I ride 16s on my EX500/GPz500R. As to tires, Bridgestone just upgraded their classic bias BT45 to make the  BT46. As you can see, they had a certain brand of motorcycle in mind.

 

 

[Kane]

Thanks, as always, for your sage elucidations! This place is awesome—-I feel like a fly-on-the wall at a post-race pit party!

It looks like I missed the boat on the LM IV. It sold before I could get to it. Nonetheless, I’ve learned a lot here. Perhaps the 16” stigma is good for the buyer given what these bikes sell for compared to the 850s.

Cheers, and I hope everyone is staying well and getting some good rides in.

[po18guy]

If anything, today's selection in 16" tires is smaller but better, since many of the offerings have all been upgraded with new compounds and some tread modifications. Many 80s-90s bikes with substantial HP use 16s. The Yamaha FJ1100 is one, the CBR900 another.

[Lucky Phil]

1 hour ago, po18guy said:

If anything, today's selection in 16" tires is smaller but better, since many of the offerings have all been upgraded with new compounds and some tread modifications. Many 80s-90s bikes with substantial HP use 16s. The Yamaha FJ1100 is one, the CBR900 another.

And the bike that Changed the handling standard for Japanes bikes back in the 1980's the GPZ900 Kawasaki. I owned one as well. Oh and the first Fireblade Had a 16 on it I'm pretty sure.

Ciao

[pete roper]

There was, and still is, a lot of horse shit spoken about the 16 inched front wheel LMIV. I was working at a shop in south London when they were a 'Current' bike and well remember the whinging and whining about how badly they handled. Thing is I could never get one to misbehave. As time went on it became obvious that those that whined most had almost invariably changed the tyre profiles from those recommended by the factory, that makes a huge difference. As does not being super observant with tyre pressures. Even a pound or two off would transform a swift and for a Guzzi agile performer into a wallowing slug.

 

If I wanted a MkIV I'd actually want it to have a 16 incher on it. I wouldn't want one though because of the horrid 'Big Valve' engine, the even ropeyer than usual gearbox and the propensity for them to loose crownwheel bolts. The 'Tall Head' frame makes them look like an adenoidal teenager as well, ugly as, bleargh. I always find it amazing they canned the MkIII, probably the best looking and certainly the sweetest riding Squarefin Tonti for the MkIV which vibrated more, carbureted worse, didn't go appreciably faster or handle substantially better but looked as ugly as a sack full of farty arseholes!

[po18guy]

7 hours ago, Lucky Phil said:

And the bike that Changed the handling standard for Japanes bikes back in the 1980's the GPZ900 Kawasaki. I owned one as well. Oh and the first Fireblade Had a 16 on it I'm pretty sure.

Ciao

Back in the 60s, my friends and I made fun of the 16" wheeled Ducati Monza 160. We're not laughing anymore. I think that Fireblade = CBR900RR in the states. 'Cept the Aussies probably got more HP.  And, GP riders didn't like the 16s, so they swapped wholesale to 17s and production bikes followed. Trouble is that the 17s slowed the steering response. So, they went with 16.5...

[Chuck]

Strange. The AeroLario is my allarounder. Grocery getter. Load it and go to rallies, etc. I've never thought of it being "twitchy" at all.

The problem I've had is finding a good 16"rear" for the AeroLario. There are several 16" fronts..

Anyone?