Avon Trailriders. Structural problem.

[san]

Hello everyone. It's time to change the tires, I decided to put an AVON Trailrider. Starting to study its characteristics in depth, I found that the front tire of dimension 90/90 21 has only a diagonal design, and the rear tire of dimension 150/70 R17 has only a radial design. As far as I know, tires of different designs cannot be installed on a motorcycle, this is fraught with loss of controllability. I would like to clarify this issue with you so that you either dispel or confirm my concerns. Thanks.

[K1W1]

As far as I know, tires of different designs cannot be installed on a motorcycle, this is fraught with loss of controllability.

That is exactly what the OEM tyres from Triumph and many others are. Cross ply on the front and radial on the rear. Cross ply tyres are less susceptible to sidewall punctures than radials (and they are no doubt cheaper) which is the argument many use to fit a cross ply to the front.
You cannot fit from a safety point of view a radial and a cross ply on the same axle. That does not apply to motorcycles but many translate that to mean you can't fit a radial and a cross ply to a motorcycle which is not correct.

[san]

Thanks for the reply. I take it these are good tires? How noisy are they, don't they hum when driving on asphalt? Is the handling on them excellent? Currently, I use the Pirelli Scorpion Trail, they behave perfectly on asphalt, in turns and on a dry dirt road, but they do not hold wet ground at all, they immediately slide. So now I want to install other tires, but I don't want to lose control on the asphalt.

[K1W1]

They are my favourite tyre and I have had quite a few but I ride a bike with a 19” front wheel so I use the 110/80 X 19 radial on the front so I cannot comment on the 21” tyre.
Rears last me 13-14000 km and are imo very quiet.

[markw]

I just had Trailriders fitted, front and back, and had one day of riding on them in the rain the day after fitting them.
And they felt just as grippy as in the dry 
No squirming going over road marking, or bitumen crack repairs and no tram-lining along ridges on the road surface.
Noise wise I think maybe slightly louder than the standard OEM Bridgstone tyres my XCA came with, maybe? But no, not enough for me to think this is a noisy tyre.
Good for light off-road use, on firm to hard dirt/gravel tracks.
Though they are Mud & Snow rated my feeling so far is that they are not going to be happy in an all out mud/snow situation or in loose sand.
But for everyday use I’m very happy with them so far.
The only thing yet to discover is how many miles they will last…?

[san]

Thank you all very much for the answers. You convinced me to buy such tires for myself.

[coach]

San;  This bias ply vs radial front tire quandary was discussed recently in depth on another thread here.  I was also in need of new tires and had the same question about this on my '21 T900 GT as I too thought mixing the two wasn't ideal.  I contacted Pirelli-USA as I was hoping for another set of their Scorpion Trail 2 tires since I've really liked them on two other bikes.  Sadly the front 100/90 19 (which is bias ply) hasn't been available anywhere in the states in that size since Spring and dealers tell me it will be October before they hope to see that size again, so I went with the Michelin Anakee Adventure tires. (which I really like) 

Pirelli-USA did reply quickly to my email question on this and they said for narrow/tall tires like my 100/90 and your 90/90 the bias ply construction is better than radial construction as the sidewalls are stronger to deal with weight on a narrow tire and better handle hard hits off-road.  No idea if this is true or just PR spin as other opinions have been voiced here about this question.  Michelin also only makes their 100/90 19 tire in bias ply so I decided to go with that as I do ride off road often in rocky terrain. I am quite happy with the handling of my T900 both on and off road with my new tires.

I hear on the T800 models Triumph has approved using either the 19" bias ply or the radial front tire, but I'm not sure about the 21" size.  (so far Triumph has not approved that choice on the T900 series)  If you only ride on well groomed pavement and have a T800, you may want to go with a radial front if it's available to you.  Clear as mud, right?  Oh well sorry, hope this helps a little, and as always YMMV.  Cheers coach 

[K1W1]

Originally Posted by coach

Pirelli-USA did reply quickly to my email question on this and they said for narrow/tall tires like my 100/90 and your 90/90 the bias ply construction is better than radial construction as the sidewalls are stronger to deal with weight on a narrow tire and better handle hard hits off-road.  No idea if this is true or just PR spin as other opinions have been voiced here about this question. 

What Pirelli said is correct. Cross ply (or bias ply) tyres are less susceptible to sidewall damage than radial ply tyres.

[san]

You know, yesterday I carefully looked at my tires, on which I drove 15,000 km. This is the pirelli scorpion trail, installed at the factory of my motorcycle. So, the front tire 90/90 - 21 is installed at the factory of a diagonal design, and the rear 150/70 R17 of a radial design. If such a combination is allowed at the factory, then I will safely install an AVON trailrider of different designs. Moreover, I had no complaints about the handling of the motorcycle on the pirelli scorpion.

Thank you all very much for your answers and help. As for me, I consider this issue resolved.