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Help MC19 2.5” front rim / tyre size?

Discussion in 'Honda 250cc In-line 4's' started by Barks, Jun 10, 2020.

  1. Barks

    Barks Active Member

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    Hi all, there’s a lot of information/threads/discussion out there on front tyre size for an MC22 but not the MC19 with the narrower 2.5” rim.

    Stock size is the now fairly redundant 100/80. Is it recommended to stick with this and the poor choice in rubber... or is it ok to fit the more ‘normal’ 110/70 to the 2.5” rim?

    The tyre/rim size compatibility charts for each brand or model of tyre shows that it is not necessarily suitable. In most cases the 110/70 calls for a 2.75” or 3” rim min.

    I know one answer is... go by the tyre manufacturer recommendation but that doesn’t leave many options.

    I guess I am asking what are people’s experiences and what front size do you run on an MC19 stock rim?

    Thanks.


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  2. Simon

    Simon Well-Known Member Premium Member Contributing Member

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    Try this size chart..lower rim width for a 110/70/17 is 2.5", 2.75" optimum and 3" at the other end of the scale. I've gone both ways in the past (both front and rear) and i'd say the difference is marginal on all the bikes I've owned on the road, much more pronounced on the track. You can also experiment with pressures which make a noticeable difference weather road or track..no experience with the MC19 though..

    www.bits4motorbikes.co.uk/TireSizeConversion.html
     
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  3. Barks

    Barks Active Member

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    Thanks Simon, unfortunately that chart doesn’t include the 110/70.

    Why should the fit and feel of the tyre change from street to track? The profile will be the same, but different to that of the 100/80.


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  4. Simon

    Simon Well-Known Member Premium Member Contributing Member

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    Hiya pal,

    Go down to the 17" rim section and you'll see it..their different on both the road and track but its only when pushed that you'll feel the difference if you stick within those rim widths..I'm not an expert but your looking at marginal amounts in terms of rate of turn/ fall or drop in and maybe a bit more on transition..they'll feel different but you'll get used to whatever you decide to go with and feel comfortable with..modern rubber with the 110/70 and lots of grip you'll feel straight away but be sure to match it with something similar at the rear! The difference is easier felt when your going all out..but not likely on public roads
     
  5. DannoXYZ

    DannoXYZ Well-Known Member

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    Yeah, you have to take it to +90-95% of limit to notice difference. Not something that's safe or wise to do on street...
     
  6. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    I'd say that the 110/70 will be fine particularly with modern rubber, just get something on the rear to match.
     
  7. DannoXYZ

    DannoXYZ Well-Known Member

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    just did quick check and these tyres come in 100/80-17 size:

    - Avon AV83 Street Runner
    - Avon AM26 Road Rider
    - Michelin Scorcher 11
    - Michelin Commander II

    Although there are over 30 in 110/70-17. I really like Dunlop Alpha-13. Super sticky and still lasted +50-days at track.
     
  8. Barks

    Barks Active Member

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    I ended up going 110/70 Bridgestone S22 to get something with real performance. The 100/80 size is very choice restricting.

    The outcome is a much steeper profile on the shoulders, you wouldn’t even use some of the rubber with the bike sliding down the track on its fairing! Change of direction is a bit quicker.

    Only used on the road so far, lockdown hasn’t helped getting on a track but happy with the choice.


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