CB125F Tyres & Sizes

[Kurzheck]

Hi everyone,

I've been looking into alternatives to the OEM chinese things on my 125, i found this thread from last year:

https://www.themotorbikeforum.co.uk/viewtopic.php?t=60093

where folks are talking about ContiGos - but Continental don't seem to think they do a ContiGo in the 'right' sizes, which is an 80/100 18 at the front and a 90/90 18 at the back:

https://www.continental-tires.com/motorcycle/tires/motorcycle-tires/allround/contigo-light-motorcycles

Would i just put the 2.75 18 on the front and the 3.00 18 on the back in that case? are they basically close enough to the original sizes that it won't be noticeable?

Cheers!

[Snod Blatter]

What a great question (and a silly choice of front size by Honda!). As you are probably aware there is a lot of choice in 90/90-18, this will have a very similar circumference to the 80/100-18 but it depends if the slightly fatter tyre will fit without rubbing - only you can see what kind of clearance you have around the front tyre as it is. 3.00-18 is virtually the same as 90/90, but 2.75 won't be tall enough.

The first number is the width of the tyre, the second number is the height which is a percentage of the width. So a 90/90 is 10mm wider than the 80-100, do you have more than 5mm clearance either side? I bet you do.

[Kurzheck]

Thanks for the reply so if i'm reading you right, what we're basically saying is that if there's space enough for the extra width, just put a 90/90 (or 3.00) on both ends?

[Snod Blatter]

Yep. The bike won't be quite as flickable because of the fatter tyre but you do get a choice of much nicer tyres so overall I'd go that way every time.

In 90/90-18 I can personally vouch for the Michelin Pilot Activ being excellent, with the Metzeler ME22 being a bit rubbish in the wet and Pirelli City Demons/Heidenau K44 being outright awful. In 3.00-18 I like the Metzeler ME77 and Heidenau K65 very much. Proper aftermarket ContiGo!'s are also worth a look, far superior to the terrible things that come on new Hondas - I have tried both and know they are not the same animal at all despite having the same name.

[WinBase]

Hi

 

sorry if this is a bit of a necro post, but i have a 2021 Honda CB125F with standard cheapo tyres of 80/100-18 front & 90/90-18 rear. although i know it's a small bike and don't expect it to be too planted anyway, but i find that especially in wetter conditions the front tyre grip just feels a tad too squirelly for my liking on bends, as it does on cobbles, so i take it much slower than i probably need to. i replaced the rear tyre a few months ago coz of a puncture with the same tyre it came with as standard, and upped the rear preload which helped, but my questions are these:

1. if i'm reading the above comments correctly, can i use contiGo's 90/90-18 on both front & rear - i think theres well enough space to fit
2. would i be safe just replacing just the front with a 90/90 for now as it's going to need replacing soon, and then the real one later with a 90/90 when due? seeing as it's only about 500 miles old. would 'mixing' cause any possible issues

any help or comments would be appreciated. Thanks

 

[Old-codger]

Stick with the standard sizes and buy a decent brand of tyre would be my sugestion, do not buy cheap crap you want a tyre you can feel confident in and grips when you need it.

[caocao]

Hey

 

Digging the dead ones out again as I REALLY need help with the levels of moronity I have achieved while researching about this topic.

 

I recently got my CB 125 F which I have been using as a daily and so far I like this small fella a lot. The only negative thing, which the previous user already mentioned, is that it really does feel a little wobbly sometimes because, boy are those tyres thin.
 

I‘m thinking to change them and looked up the recommended sizes. For now the Heidenau K66, 90/90-18 57H seem to be a very good choice but being the idiot I am, i still think 90/90 is very thin (I know fatter tyres mean changed dynamics etc. but I‘m not looking to win any races and ride this thing mainly to work and as a daily).

 

Can someone please elaborate to me what the FATTEST possible tyre width for my model would be? I wasn‘t able to find this information even on Hondas Webpage and neither on Heidenaus. Would a 120/80 fit if I go down from 18 to 17inch wheels? I seem to be unable to find this information as my brain seems to be fried from being online too much.
 

many many thanks in advance

-maurice

Edited February 17 by caocao

[Simon Davey]

3 hours ago, caocao said:

Hey

 

Digging the dead ones out again as I REALLY need help with the levels of moronity I have achieved while researching about this topic.

 

I recently got my CB 125 F which I have been using as a daily and so far I like this small fella a lot. The only negative thing, which the previous user already mentioned, is that it really does feel a little wobbly sometimes because, boy are those tyres thin.
 

I‘m thinking to change them and looked up the recommended sizes. For now the Heidenau K66, 90/90-18 57H seem to be a very good choice but being the idiot I am, i still think 90/90 is very thin (I know fatter tyres mean changed dynamics etc. but I‘m not looking to win any races and ride this thing mainly to work and as a daily).

 

Can someone please elaborate to me what the FATTEST possible tyre width for my model would be? I wasn‘t able to find this information even on Hondas Webpage and neither on Heidenaus. Would a 120/80 fit if I go down from 18 to 17inch wheels? I seem to be unable to find this information as my brain seems to be fried from being online too much.
 

many many thanks in advance

-maurice

 

I'm unable to answer your question, but changing tyres, and especially changing wheels to achieve less "wobbly" handling for so little difference seems like way too much effort for a 125. 

Narrow tyres won't cause a wobble, but low tyre pressures will. 

[RideWithStyles]

You can blame the Indian and neighbour market for that decision.

michelin do the road classic in a 90/90/18 but it is bias ply so it will be solidly built, but better bet than the Heidi.

you can’t do down a size unless you change the complete wheel(s), and the rim will be your limit for the ratio change.

changing the ratio (especially what your thinking of) or profile doesn’t always mean more grip, more than likely it will make it worse as the tyre will have less support from the sidewall, then you’ll have to add even more pressure then you’ll get this ill match balance feeling from the tyre, especially on a small road bike.

nearly all modern road and race 250bhp monsters even the fronts are still 120/70/17…..for 125 8hp right up to 1300 250+hp and kg monsters - the same front…

the cbf125 had a front 80/100/17 rear 100/90/17, still skinny tyres, I never lost the front and I road it safely but aggressively. wife fell a cropper twice, diesel in the winter on a round about (rear) and the worst chipping bitmin left over on the road I’ve ever seen (front and abit rear).

 

SD is correct, and I’ll add one more for now.

“Wobbly” have three normal causes that need looking at first;

tyre pressures.

tyre wear.

suspension.

Fork oil change will be on the cards, even if your 45kg fully clothed and wet…

They weren’t very supportive when new for more westerners, Due to their age now oil will be thinner than water and thick, gunky at the bottom,smell really bad the handling will have degraded even more so.Pictures of your old tyre wear will confirm so.

unless your a small bean pole id wouldn’t bother with 10wt, 20wt will be better bet with that type of fork.

Edited February 17 by RideWithStyles

[billysugger]

Try this site, it may help you decide

 

https://ridewrightwheels.com/pages/motorcycle-tire-wheel-fitment-chart?currency=USD

[bonio]

I'm with @Simon Davey on this. Also, if you've let your tyres get worn out and develop a flat profile, that can make the bike wobble when you're rounding a bend or corner. If that's the cause, all you need to fit it is new tyres and the wobble goes. But your bike shouldn't wobble when the tyres are set up right, even with the stock width.