why 190 rear?

[ReggieGasket]

I see some of you are using a 190/55 rear tyre when the standard is 180/55. I normally stick to standard sizes, but interested to know why the 190/55?

[D-Rider]

I use the 180 section myself .... however:

• 1) The Mille uses the 190 section tyre and the wheels are the same and the chassis geometry is virtually identical to the Falco
  
  2) I believe that 190 section is the normal section tyre for the rim width of our rear wheels

My own view is the 180 works well so why change it - especially as a 190/55 on the same rim as a 180/55 would have a slightly more gentle profile and, presumably, be a bit less keep to turn in to corners

EDIT:
Just realised I've gone into numpty idiot mode (yes I'm sure that admission will turn up in Aladinsaneuk's sig ... or Ligloo's)
Of course the 190 section tyre is the one that would have the less gentle profile on the same rim and will have the better turn-in characteristics.
Sorry for the brain fart ...

[mangocrazy]

This is a very interesting topic (if you're a tyre geek, like me), and there are no real hard and fast rules. But it's probably (he said, hedging his bets) true to say that a 190 section rear tyre is the 'correct' one for the Falco's 6" rear rim.

Basically all rim widths have a range of tyres that will fit them. Some are more preferred than others, but a number of different tyre widths can be fitted to a particular rim. The table goes something like this:

Tyre size..........................Rim size
150/70
160/60...............................4.5"
170/60

160/60
170/60...............................5"
180/55

170/60
180/55...............................5.5"
190/50 (or 190/55)

180/55
190/50 (or 190/55)..............6"
200/50

Basically the 'middle' fitment for each of these rim sizes is the one that manufacturers tend to recommend. So the Falco, sporting as it does a 6" rim and a 180/55 tyre, appears to be a bit off kilter. In fact (as practice has shown) it's a very good choice. When the Falco was initially released, the only other alternative was the 190/50.

I once owned a TL1000S (the original "widowmaker") and that had as standard a 190/50 on a 6" rim. It was horrible. The thing ran wide both on the way into and out of corners, due to the mismatch of pointy 120/70 profile at the front and the wide, flat 190/50 profile at the rear. I scrubbed the damn thing to the edges in the very first 30 miles of its life, FFS and I wasn't riding hard.

However replacing the 190/50 with a 180/55 sharpened the handling up immensely; fitting a rear 5.5" rim off a GSXR600, shod with a 180/55 was the real deal but we won't go into that. Around that time, the generally accepted wisdom became that a 180/55 with it's more pointy profile compared with a 190/50 was the way to go if you wanted your 6" rim-shod bike to handle.

It's worth mentioning here that designations such as /55 are an indication of the 'aspect ratio' of the tyre; i.e. how 'tall' it is (the 180 indicates its nominal width in mm). This is the ratio of the height of the tyre sidewall, (section height), expressed as a percentage of the width and is known as the aspect ratio. In this case, 55% of 185mm is 99mm - the section height. A 190/50 tyre has a section height of 95 mm, and a 190/55 (see, we got there in the end) is 104.5mm tall.

So from the above we can see that a 190/50 has the lowest section height (i.e wide and flat), a 180/55 is taller and narrower, and a 190/55 is wider and taller still. Until the advent of the 190/55 section tyre, people who wanted a bike that handled stuck religiously to the 180/55 on a 5.5" or 6" rim. In fact, when buying a set of Marchesinis for my 888 SP3, John Hackett specifically advised me to go for a 6" rim and put a 180/55 on it.

I spoke to him again recently on the same subject and he said that now his recommendation would be to go for a 190/55, purely because of the extra rubber on the road at big angles of lean. The extra section height of the 190/55 also effectively raises the rear ride height by approx 5mm, pretty much negating any slower steering caused by the wider tyre.

For what it's worth, I'm intending to put a set of 120/70 and 190/55 Michelin Power One tyres on my 888 and do a couple of track days next year. I'll let you know how it goes...

[Falco9]

Both the 180 and the 190 profiles are approved for the Falco indeed some Falco's were delivered with 190/50's on them

I've been running a 190/55 on the Tuono and to be fair its been great. I thought it would speed up the steering a bit more than the std 190/50 but to be totally honest I couldn't really feel any difference on the road.

I personally like the "planted" feel the 190 gives especially in long fast sweepers, I also like the fact you use more of your front tyre with a 190 rear, but thats just a personal thing

I'd be tempted to run a Falco on a 190/50 rear but with the forks dropped just one ring in the yokes. Just my personal opinion of course

F9

[ReggieGasket]

Thanks for the comprehensive information here; fantastic. I tend to prefer a narrower rear tyre on a road bike, as I don't really get that banked over and it seems more efficient. However, I think it is a good idea to try different profiles to see what suits you. I intend to have a spare set of wheels with track tyres on in summer and I may be tempted to go for the 190 section. However, I'll be buying used track tyres, so it depends what the racers are using - my guess is 190/55, but it's a few years since I bought any.

[DavShill]

My wife read this thread (over my shoulder) and thinks we are all very sad .

They just don't understand do they!

[Falco9]

My wife read this thread (over my shoulder) and thinks we are all very sad .

They just don't understand do they!

No Dave, lets be honest she's right. We are that sad but we're happy and that's what counts eh?

F9

[mangocrazy]

However, I'll be buying used track tyres, so it depends what the racers are using - my guess is 190/55, but it's a few years since I bought any.

I'd bet my mortgage that racers would use 190/55.

[D-Rider]

LOL - I'll bet my mortgage on anything ...... (it's good to have paid it off at last)

[Firestarter]

However, I'll be buying used track tyres, so it depends what the racers are using - my guess is 190/55, but it's a few years since I bought any.

I'd bet my mortgage that racers would use 190/55.

Maybe a question for Griff, for someone who's on the other forum with him? I'm sure he'd know which is generally used

[ReggieGasket]

Hang on a minute. There's nothing sad about this thread. I wouldn't expect anyone to appologise for what they enjoy. My wife spends ages looking at her Boden catalogue with my daughter. Sad too? Not really. Tyres are fantastic!!!

[rick]

just had a look at my rear wheel... maybe 5mm before lower part of chain hits tyre... running a 180... definitely couldnt have a 190

[Nooj]

I like my 190/50. I always felt the 180/55 flopped into corners, the 190/50 rolls nicely from side to side.

[rick]

I've read some good things about the 190... but like I say... how much clearance do you have to your chain? I can't imagine being able to fit a 190 to mine... post a pic of the clearance, I'd be very interested!

[Tweaker]

Mine came with a 180 and, when it was due for replacement, I went for a 190 - because I could. TBH, yes, it felt different and turned in better but, I'm pretty sure that was mostly due to it being nice and round and not squared off any more. I've stuck with a 190/55 ever since cos it suits me and I'm not sure that, for the road, it would make much difference to me anyway. I've never had any chain clearance issues either.