Tyre Selection 1974 commando

Alan L · Apr 19, 2021

Hi all,
excuse me asking the same old chestnut about tyre selection. I’m sure it has been asked many times before but I’m battling with the search function on this forum.
So, what is the preferred tyre for a standard 1974 850 Commando in Australia. I guess my preference is more directed towards performance as I probably won’t be doing huge mileage.
Any advice gratefully accepted
al

Fast Eddie · Apr 19, 2021

Avon Roadriders IMHO.

Just bear in mind that with stock sized wheels you’ll be using ‘universal’ tyres which have less tread depth than a dedicated rear. So mileage will be considerably reduced on the rear.

But there’s plenty who swear by TT100s. And they certainly have a more period appearance, if that’s a factor for you.

ntst8 · Apr 19, 2021

I've just gone back to TT100's, 3.60 on the front and 4.10 on the back.
New just prior to a recent 3000km run and they will do a few more trips that length.
Cant say that i noticed any less grip than with the roadriders. I'm not a crazy rider but not a complete nanna either.

Bernhard · Apr 19, 2021

Fast Eddie said:
Just bear in mind that with stock sized wheels you’ll be using ‘universal’ tyres which have less tread depth than a dedicated rear. So mileage will be considerably reduced on the rear.

I wonder what you really mean?
Don't understand the content or recognise this
reply.
Do you mean that there really is an, - as you put it, "dedicated rear" motorcycle tyre that the average guy can get 30,000 miles from it?

possm · Apr 20, 2021

As a former rep for the NZ Dunlop & Metzler distributor if you want to go to TT100's I would recommend using a 100/90x19 TT100GP for the front with the normal 410x19 TT100 for the rear, the 100/90x19 TT100GP is about half way between a 360x19 & 410x19 and the GP compound is softer [don't fit to rear unless racing] another option is Avon's either Roadrunner or Roadriders, I have a set of Roadriders fitted to a Mk3 I am currently building though am not to the stage that I can ride it, I previously had the TT100 combination that I suggested fitted to a MK2A that I sold last year, a good combination though rear tyre millage of aprox 3000 miles, of course the roariders re yet to be tested though I had Roadrunners fitted to several of my bikes in the late 70's / 80's but my memory ain't that good!

Fast Eddie · Apr 20, 2021

Bernhard said:
I wonder what you really mean?
Don't understand the content or recognise this
reply.
Do you mean that there really is an, - as you put it, "dedicated rear" motorcycle tyre that the average guy can get 30,000 miles from it?

And I wonder what you really mean... especialy from someone who has been on this forum and around motorcycles for as long as you.

See link below. Roadriders come in dedicated front, dedicated rear, and universal fitment.

‘Universal’ tyres have 5.6mm of tread (that‘s only 0.6mm more than a dedicated front tyre) whereas dedicated rear tyres have 7.5mm.

That’s 35% more tread on a dedicated rear vs a universal. That’s 35% more mileage from a tyre.

There is no dedicated 19” rear. The only option for a 19” rear on a Commando is a universal with 5.6mm of tread depth.

A lot of folk do miss this and simply label the Roadriders as having very low mileage. But whatever the mileage, 35% less is 35% less!

I have no idea where the comment about the average guy getting 30,000 miles from a tyre came from Bernhard, especially at this time in a morning... bit early for the booze innit ?!?

ROADRIDER MKII

Designed for motorcycles of all ages, the Roadrider MKII provides a step forward in performance and reliability over its predecessor.

www.avontyres.com

Time Warp · Apr 20, 2021

Fast Eddie said:
I have no idea where the comment about the average guy getting 30,000 miles from a tyre came from Bernhard, especially at this time in a morning... bit early for the booze innit ?!?

Perhaps Bernhard has ROHAN-19 ?
#
Those fancy dedicated front and rear fitment Continental Classic Attacks in 100/90/19 have the same tread depth which is a surprise, almost like they are the same tyre/tire with the fitment arrow reversed.

Bernhard · Apr 20, 2021

Time Warp said:
Perhaps Bernhard has ROHAN-19 ?
#
Those fancy dedicated front and rear fitment Continental Classic Attacks in 100/90/19 have the same tread depth which is a surprise, almost like they are the same tyre/tire with the fitment arrow reversed.

Thanks for the insights you two! No brooze involved- honest!
BTW at least with the Conti TK17 rear with average riding you could get, yes- I actually did several times, 15,000 miles . - they are no longer available/ made, unfortunately.

Bernhard · Apr 20, 2021

Any tyre marking on those dedicated rear Avon tyres?
(To determine them from the plain ones)

Fast Eddie · Apr 20, 2021

Dedicated tyres (be they for front or rear) only have one arrow to show direction of fitment.

Universal tyres have two arrows, one for front fitment and one for rear fitment.

But the only way to know for sure is to look at the tyre size etc and cross refer to the info in the link I posted.

For clarities sake, in the link the tyres a marked F, R, or F/R. In case further clarity is required here:
F = Front (ie dedicated front fitment).
R = Rear (ie dedicated rear fitment).
F/R = Front / Rear (ie universal fitment).

There aren’t any ‘plain ones’...

This is the two arrows marked on a universal fitment tyre (in this case a 100 / 90 19 I’m using as a front):

This is the single arrow marked on a dedicated rear tyre (in this case a 4.00 18):

Bernhard · Apr 20, 2021

I'm bemused you need to go into such detail over a simple question on rear tyres.
I can see that if you ask for a dedicated rear tyre, and there was none in stock, the tyre shop could supply you with the one with the less tyre thread than the one you specifically asked for and you'll be none the wiser, unless, hthat is, you took along a thread gauge and found you had 1.9mm less thread. . .. . .mmmmmmmm!

Fast Eddie · Apr 20, 2021

You are bemused that someone takes the time to try and answer your questions fully?!

You’re the one that seems to be struggling with this concept for some inexplicable reason Bernhard. I went into detail to try be explicitly clear, to the point of avoiding questions and unnecessary remarks.

I failed !

But, for what it’s worth, I think your concern is unlikely, I can’t see an example whereby what you’re suggesting could happen with the sizes we use on old bikes.

Bernhard · Apr 20, 2021

Fast Eddie said:
You are bemused that someone takes the time to try and answer your questions fully?!

You’re the one that seems to be struggling with this concept for some inexplicable reason Bernhard. I went into detail to try be explicitly clear, to the point of avoiding questions and unnecessary remarks.

I failed !

But, for what it’s worth, I think your concern is unlikely, I can’t see an example whereby what you’re suggesting could happen with the sizes we use on old bikes.

You haven't worked in the motor tyre trade -I have!!

Onder · Apr 20, 2021

Nobody seems to cater to the old bike 19" rear crowd. Well obviously the problem is there is no crowd.
Which is why intelligent types (not I) fit a 18" rim so they can get dedicated rear tyres.
Instead I mindlessly get 3k per rear tyre. If you are energetic, you can move the fronts to the rear and the
new tyre to the front as if you don't the fronts never wear out just get to be life expired.

Fast Eddie · Apr 20, 2021

Bernhard said:
You haven't worked in the motor tyre trade -I have!!

My point is, there are no same sized tyres that could allow that mix up to occur. I won’t go into detail for risk of causing further bemusement.

The only way it could happen is if the dealer fits a different sized tyre. And you’re right, this can happen, and we should ALWAYS check that the exact size and rating of tyre we ordered has been fitted.

Staytite · Apr 20, 2021

Alan L has not stated his front and rear rim sizes, which will start another well worn discussion.

Onder states "intelligent types fit 18" rear rims so they can get dedicated rear tyres"

Fast Eddie being an intelligent type ( I'll PM details of my bank account for payment of fees due for approval ) has fitted an 18" rear rim.

But FE being super intelligent (further fees incurred) has studied the Avon website in detail and found :
- 100/90 x 19" front (5.6mm tread) has an overall diameter of 671 mm
- 400 x 18" rear (7.5mm tread) has an overall diameter also of 671 mm
Bingo the same, thus keeping his Commando roughly level.

I think being level is important (joke intended). Or am I wrong?

Onder · Apr 20, 2021

Same diameter when you are finished is important.
Advise worth what you paid for it.

worntorn · Apr 20, 2021

Yep, my biggest mistake in switching to alloy rims on the Commando was staying with the 19" rear.
With the Vincent I switched to 18" and run the 400x18 Roadrider, which is a nice chunky tire with good weight carrying capacity, and the deep dedicated rear tread.
Those tires run for about 6500 miles, two up. If I want to try a different brand, there are plenty to choose from.
The Norton's 100/90/19 Roadriders are gone in 4500 miles, solo riding. Two up is best avoided as it's an overload for the 100/90/19.
The only other tire for the 19" rear is the Dunlop.
I bought into the silly idea that Commandos must have 19" rims front and rear to handle properly.
First off, Commando handling is not particularly special, although it's fine. I don't believe the switch to an 18" wheel, with tire at the same diameter as the 200/90/19, would make a hill of beans difference to handling.
It might be better two up as the 19 is overwhelmed.

Glen

Fast Eddie · Apr 20, 2021

Staytite said:
Alan L has not stated his front and rear rim sizes, which will start another well worn discussion.

Onder states "intelligent types fit 18" rear rims so they can get dedicated rear tyres"

Fast Eddie being an intelligent type ( I'll PM details of my bank account for payment of fees due for approval ) has fitted an 18" rear rim.

But FE being super intelligent (further fees incurred) has studied the Avon website in detail and found :
- 100/90 x 19" front (5.6mm tread) has an overall diameter of 671 mm
- 400 x 18" rear (7.5mm tread) has an overall diameter also of 671 mm
Bingo the same, thus keeping his Commando roughly level.

I think being level is important (joke intended). Or am I wrong?

Well, intelligent or otherwise, you have exposed my intent! Max tread depth and same sized diameter front and rear, plus large contact patch for front, was my thinking way.

I do sometimes think the slightly narrower 3.25 19 might give a quicker turn in, but its a smaller diameter and contact patch, so I’m happy with the current trade off on mine.

BTW... OP did say his bike was standard, which I interpreted as meaning standard 19”s...

Time Warp · Apr 20, 2021

Onder said:
Nobody seems to cater to the old bike 19" rear crowd. Well obviously the problem is there is no crowd.

Continental do.

100/90/19 fronts.
100/90/19 and 110/85/19 rears plus a 120/90/18.

All are radials but not suited to the stock rim widths.
#

The OP is pretty much stuck with the tyres mentioned in previous posts if stock WM2 rims.

Tyre Selection 1974 commando

Alan L

Fast Eddie

ntst8

Bernhard

possm

Fast Eddie

ROADRIDER MKII

Time Warp

.......back to the 70's.

Bernhard

Bernhard

Fast Eddie

Bernhard

Fast Eddie

Bernhard

Onder

Fast Eddie

Staytite

Onder

worntorn

Fast Eddie

Time Warp

.......back to the 70's.

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