This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

19 v 18 rear wheels/tyres

P

popup

Joined Feb 2006
310 Posts | 4+
maryborough.queensland
anyone know the reasoning behind,why motocross's have 19" rear tyre/wheels & enduro has 18"?
i know my mate who bush bashes his crf450 which has a 19" rear,his always seems to be more prone to getting flat tyres than us with the 18"tyres.
i done a weight test on the retread tyres that we are using.
the retreads use the same tread pattern for both 18" & 19",same size knobs.
the dunlop/bridgestone/michelin side walls with retread cap weighs in @ 6.6kg in the 18"
the dunlop/bridgestone/michelin side walls with retread cap weighs in @ 5.9kg in the 19"
even though thats about 700g lighter, they would have to end up much the same weight ,taking the 19" would have a larger rim.
whats the theory?
..weed..
 
I don't think weight has anything to do with it. I believe moto-crossers use the 19"s because they have less sidewall flex in corners as well as less flex during acceleration and braking. The outside circumference of both 18" and 19" tires is the same (or close) meaning the 19" has a low profile sidewall. Less sidewall is the reason 19's are more prone to flats and aren't recommended for off-roading away from the track.

That's my theory, but I've been wrong before.
 
agree with logjump.

while i'm here, anyone in the UK got a 2.5 x 18" or even a 2.5 x 19" rear wheel i can use?

a forlorn request but i will anyway...

carry on everyone!

regards

Taffy
 
It appears to be a way manufacturers promote their Woods/MX offerings and a bit more promotional benefit, rather than an actual benefit. Other than you have less tire choices for the 19". I bet 9 out of ten riders could never actually tell a difference. I could be wrong.
Mark @ SOS
 
Bet?

And what do you bet?
It`s a big difference at least in the tricky stonetracks we have here in Sweden.
With 19" you don`t have the same grip beacuse you have to have so much pressure in the tire to not punkture it.
With the 18" i have 0,6- 0,9 kg pressure depending on the track and have good grip in the wet stony tracks we have here.

Regards
Jampe


TeamSOS said:
It appears to be a way manufacturers promote their Woods/MX offerings and a bit more promotional benefit, rather than an actual benefit. Other than you have less tire choices for the 19". I bet 9 out of ten riders could never actually tell a difference. I could be wrong.
Mark @ SOS
Click to expand...
 
There you have it! Unless nine more people weigh in and say they can't tell the difference as I said before, I could be wrong.
Mark @ SOS
 
i don't think anyone has said anything wrong so far mark. less choice of tyres because the MX'ers do less types of work on less variety of weights. punctures being the main reason i'd have thought and don't forget - they have the same rolling circumference. so...

regards

Taffy
 
I was actually referring to trials tires when I mentioned less choices. I'm not aware of anyone making a 19" trials tire. I know why they don't make that. I can see the point about side wall exposure, that makes good sense.
Mark @ SOS
 
i can feel the weight difference going between 2 18s one 6.5kg and the other 7.8kg, havent tried 19 vs 18 on the same bike but I reckon Id feel it. heavier tyres need a softer rebound setting too.

18s are better in sand because you don't have to run 2psi like the 19's get a big enough footprint,

on my yz400 i had to run 2 huge steel rimlocks and 3-4 psi to get similar performance to 8psi on the 18s.

same on the front I run the biggest profile I can get to increase the footprint.

also don't think you can get 150 -90s and 140 90s in 19? the IRC MB5 and the tyranoflex big tyres come in 18s

we're running paddles with bolts now though, different story altogether :D
 
I suspect that the weight difference is very small, depending allot on tire size of course. But the weight of the pkg can certainly make a huge difference, just ask my friend David, he ran the new Tubless set-up on the front of his 09 FE450 and the steering became exceptionally squirrely. Surely one of you longtime off roaders can give us a history lesson on the reason for the split. Maybe there is some vintage marketing material that can give us some insight.
Mark @ SOS
 
yep, sounds about right.not about weight at all.
i too have just put the tubliss tyre system in the front & rear of my berg,but so far have only tried it in soft sand.i'm thinking the 01-08 bergs are probably a bit more front wheel bias than the 09 model.might actually be a disadvantage running tubliss on 09 model bikes, unless the footpegs are weld on further forward.
what is the front/rear wheel weight bias on the 09's anyone put them on the scales yet?
its almost 50% on mine 62kg front & 63kg rear.
weight saving on the tubliss rear over tube was .9kg
weight saving on the tubliss front over tube was .75kg
should be interesting to see the difference between wal's std fe550 & my o'l slugger
bushy,might be worth a try with one of those huge rock ape tyres(teraflex) & a tubliss.
might not suck so much hp out of it trying to swing it around.
..weed..
 

Similar threads

L
Have 19" Blue Berg Rear Wheel, lookin to trade to 18" Blue
Replies
6
Views
2K
CrazyTed
C
H
Buying a new FE570? Known issues, problems & common mods
Replies
82
Views
64K
linnell
L
pollo
Dunlop Geomax MX 51
Replies
0
Views
1K
pollo
pollo
D
Dale E O's 2009 Idaho City 100 ride report
Replies
13
Views
3K
kzoo
K

Register CTA

Register on Husaberg Forum! This sidebar will go away, and you will see fewer ads.

Recent Discussions

Recent Discussions