Basket Cases

[David Lahey]

For a few years now I've been seeking the best tyre to fit on the back end of Alpinas.
Like all 5 speed s, the chain on my 350cc model 138 Alpina is closer to the middle line of the bike than many other bikes of the era. This limits the width of the rear tyre that can be fitted. A stop-gap tyre for my model 138 Alpina has been to run a Michelin X11 trials tyre on the back but they do shred quickly during spirited riding. The original tyre fitted to Alpinas was a narrow and flexible Pirelli knobby that was fairly universally disliked by riders and also shredded quickly.
Nowadays the KTM Freeride 250 and 350 are some of the bikes that fill the market niche that the Alpina filled so well in the 1970s and the Freeride comes fitted with these MAXXIS 4.00R18 tubeless tyres. Plenty of KTM Freeride buyers swapped the MAXXIS out for something they preferred before even riding them.
That process of people taking new MAXXIS off their showroom KTMs is why there have been some MAXXIS tyres getting about on other bikes. I tried buying a rear MAXXIS to try out a few years ago but there were none around here removed from new KTM Freerides and the local KTM dealer could not even supply them as a KTM spare part.
At some point in the last few years the MAXXIS importer started importing them and I recently bought one to try out.
One reason I'm keen to try the MAXXIS rear out is that some friends have been running them on their trials bikes and reckon they are a pretty good thing for trials riding. I figure if they come off a Freeride and work well on a trials bike then they might be perfect for a Alpina. I do need to do a test-fit though to see if it clears the chain because they are a little bit wider overall than a Michelin X11.
I might even try this one on a twinshock trials bike first to see how well the bead seats onto a tube-type rim (the MAXXIS is a tubeless radial tyre)

[Greg Harding]

Hi Everyone,
David, with all this workshop time in the sunshine state makes me think it might be a little warm to go riding? It will be interesting to compare notes on MAXXIS Tyres as I have a little experience....

Twinshock Masters 2015

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On both ends of Kermit at Twinshock Masters

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FRONT TOO!

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Even on the TLAhhhh

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Basically just forget what you have learnt about pressures with Michelin Trials Tyres. All Tyres age harden so maybe use fresh Tyres for Trials and when they get hard, then fit to the for less wear.

My first experience with MAXXIS Trial MAXX Tyres were when I put the very first kilometers on 2015 KTM Freeride 250 two stroke. The first model Freeride was a 4 Stroke 350 and it came fitted with Dunlop Trials Tyres (D803 I think)? Yes I got to test ride that one as well and in my opinion, the Trials Tyres were ALL of the Trial component and the rest was just dirt bike!

The 250 was definitely an improvement as it was SO much harder to stall and had better tractable power delivery. Interestingly there is a wire under the instruments that you can pull out to make it even better, go figure? Apparently if the fuel supply is crap, then you pull the wire out and it retards the ignition (or alters it at least) to cope with low grade fuel. The MAXXIS Tyres impressed me on the RED CLAY we have here in the hills so I started buying them.

Definitely try fitting the rear MAXXIS to a tube type rim WITHOUT adjusting the bead area. At first I did not realize they were tubeless as the Freeride 250 had tubes in both ends, yes I had to replace both of the cheap crap tubes on Detour.

Fitting the rears was easy as they went on without dramas even on the tube type rim and the TLAhhhh has powder coated 2.15 tube type rear rim which is a fairly slippery coating.

My experience with Michelin Tubeless Tyres on Donna's powder coated 2.15 tube type rear rim was no where near as enjoyable! Mutter Mutter Mutter.

Can you please do a new tyre bead area comparison photos on Rear MAXXIS and Michelin? Maybe an inner diameter comparison of the bit you trim on a Michelin?

[David Lahey]

I'll do bead profile photos later on but I did get to do some bead internal diameter measurements this morning.
It's not easy to get the diameters because unfitted tyre beads are not completely round. I measured the diameters at 4 locations (0, 45, 90 and 135 degrees) without moving the tyres and used the averages. I found that the sharp (inside) edge of the Michelin bead was about 10mm smaller diameter than the sharp (inside) edge of the MAXXIS bead. The wedge angles are very different.
The blunt (outside) edge of the Michelin bead is also a smaller diameter than the MAXXIS and even harder to measure but I would say it is something like 3mm smaller diameter on the Michelin.
They are so different that it's difficult to believe that both tyres are designed to fit on the same rim design. Maybe the longditudinal stiffness of the bead reinforcement is lower on the Michelin (maybe the MAXXIS uses steel wire and the Michelin uses polyester cord)
Later on:
I just took some photos and also weighed the tyres.
Before I post up the weights does anyone want to have a guess of the weights?

Photos showing the difference in the bead edge angles.

How I took the photos:

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MAXXIS

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Michelin

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[David Lahey]

So my weekend included MAXXIS tyre fit testing.
It took a lot of pressure to get the MAXXIS up onto the bead seat of a well-cleaned 1.85 TY175B rim and it kept sliding off when the pressure came down anywhere near trials pressure. I even left it overnight with the bead up on the bead seat but as soon as the pressure came down again it slid off.
My next move was to test just removing the taper from the bead. It didn't take long with the flap-wheel to do this, maybe 5 minutes.
Test fit again on the same rim and it went up onto the bead seats at 40 psi lubed with a weak dishwashing liquid mix. I left the tyre clamp loose and let it down to 6 psi and it stayed on the bead seat. If I let it down to zero it slid off.
I then pumped it up to about 20 psi and tightened the tyre clamp, let it back down to 6 psi, which felt about right, and refitted the wheel to the Majesty and went for a trials practice session at home.
6 psi was just right for my weight and that tyre. I don't know why but the MAXXIS needs a bit more pressure than an IRC or Michelin X11 to work right. I would normally use 3-4 psi with IRC or Michelin.
I reckon the grip on dry dirt and gravelly steep stuff with the MAXXIS is very good - maybe even a bit better than a trials tyre but that's all I've got at my place at the moment. I still want to test it out in wet stuff and especially on wet roots and wet branches and logs because I'm not sure it conforms to small smooth things as well as a trials tyre does. Here's hoping for some rain.
While I was covered with rubber dust from shaping the MAXXIS tyre beads, I shaped the beads on a Michelin X11 too. The Michelin required a lot more rubber removed. The Michelin took about 20-25 minutes to do while the MAXXIS was about 5 minutes and the size of the pile of dust after doing the Michelin was proportionate to the time it took to do.

[David Lahey]

While I was working on the Majesty to try out the MAXXIS rear tyre, I noticed a clunk at the swingarm pivot.
As usual the inner steel bush had rusted and worn down and chewed out the plastic bushes.
I was prepared for this, having bought a couple of new inner bushes a while back. stopped making them donkey's year ago.
One is a "new" old stock Yamaha part that cost me an arm and a leg on eBay.
The other is an aluminium one I bought from the UK a few years ago. It was more sensibly priced than the NOS bush but I admit to having trouble with the idea of using aluminium in the place of hardened steel.
I'm wondering if it might corrode less than the steel in that application and maybe last longer? It looks like it has been clear anodised.
Has anyone tried one of these aluminium bushes?

[Greg Harding]

Hi Everyone,

They are so different that it's difficult to believe that both tyres are designed to fit on the same rim design. Maybe the longditudinal stiffness of the bead reinforcement is lower on the Michelin (maybe the MAXXIS uses steel wire and the Michelin uses polyester cord)
Later on:
I just took some photos and also weighed the tyres.
Before I post up the weights does anyone want to have a guess of the weights?

David, I remember reading the blurb somewhere about Michelin spending a fair bit of time and care designing the X11 Tubeless tyre bead area most likely because of expected low pressures. Maybe it is over designed? Definitely hardened steel ring inside the bead as I have cut them experimenting but not so with the MAXXIS!

Also in a different article about Michelin being slammed about the weight of an X11, so they came up with the "X light" so I think you are asking a trick question about weights? My guess/es is if you have an X11, then 6.1 kg, if you have an "X light" then 5.9 kg? For the record Dunlop D 803 comes in halfway at 6 kg so I am guessing MAXXIS and "V rubber" are about 6 kg to avoid being ridiculed like the overweight X11?

So my weekend included MAXXIS tyre fit testing.
I reckon the grip on dry dirt and gravelly steep stuff with the MAXXIS is very good - maybe even a bit better than a trials tyre but that's all I've got at my place at the moment. I still want to test it out in wet stuff and especially on wet roots and wet branches and logs because I'm not sure it conforms to small smooth things as well as a trials tyre does. Here's hoping for some rain.

David, here are some photos of rims comparing the widths:

Yamaha 1.85 and Montesa 1.85

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Yamaha TY 250 A 2.15 and Montesa 1.85

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Yamaha 1.85 and Montesa 1.85

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Now you can see, the rim profiles are very similar and there is not much of a ledge on either for the bead to grab.

As I previously stated, I competed at Twinshock Masters on Kermit with MAXXIS on both ends with no issues of bead popping in. No modifications to bead area or rim and the only thing I can see that is different is the rim is narrower than ! The 2.15 "A" model rim is a better choice and you will never guess what I did with the powdercoated 2.15 rims!
Oh and the other thing is they went on dry, why are you lubricating the bead?
Also, why are you referring to the MAXXIS as something other than a trials tyre? They are trials universal pattern, feel like licorice when new and it even says "TRIAL" on it:

MAXXIS TRIALMAXX

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[Betaman]

If you look at the maxxis website Greg you will find they call their tyre a hybrid.
Altho I dunno where a tubeless radial 18" with soft trial compound becomes a hybrid.
All I can pickup is it's slightly wider knob spacing which potentially makes it the ultimate muddy trials tyre

[The Hell Team]

If you take a close look at the MAXXIS tyre it has more open blocks compared to a true trials Universal tyre. Even though they look roughly like a Trials pattern they have bigger gaps, so are not technically a legal Trials tyre. I had a quick look at the FIM regulations and couldn't quickly find the chapter, but I am sure I have seen somewhere the measurements a Trials pattern must fit. I'll try and dig it up when I have a few minutes.

[David Lahey]

If you take a close look at the MAXXIS tyre it has more open blocks compared to a true trials Universal tyre. Even though they look roughly like a Trials pattern they have bigger gaps, so are not technically a legal Trials tyre. I had a quick look at the FIM regulations and couldn't quickly find the chapter, but I am sure I have seen somewhere the measurements a Trials pattern must fit. I'll try and dig it up when I have a few minutes.

Here's the 2021 FIM Techincal Rules for anyone who wants to have a look at what Paul is talking about

[TrialsRoss]

If you take a close look at the MAXXIS tyre it has more open blocks compared to a true trials Universal tyre. Even though they look roughly like a Trials pattern they have bigger gaps, so are not technically a legal Trials tyre. I had a quick look at the FIM regulations and couldn't quickly find the chapter, but I am sure I have seen somewhere the measurements a Trials pattern must fit. I'll try and dig it up when I have a few minutes.

Wouldn't it be really handy if someone imported the IRC Trials tyres again and offered them at a good price?