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Can you stick a larger than recommended rear tyre on?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Kbatt, Mar 16, 2012.

  1. Faced with the prospect of having to buy new tyres for the old girl. I've been looking at a pair of reasonably priced Michelin Pilot Powers for my VTR 250. However. The OEM tyre size on the rear is recommended as 140/70 17 where as the tyre available is a 150/60 17. After doing a bit of investigation, there are a few people claiming there are no huge disadvantages apart from losing a small amount of top end speed but the extra width gives added grip which apparently more than makes up for it.



    Thoughts?
     
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  2. I wouldn't do it only because the manufacturer probably went to great lengths to test and recommend the best size tyre for the bike. You could probably get away with it with no worries, but it would play on my mind too much.

    Maybe i'm getting older and more cautious - I mean, back in my 20's I had no problem flying on Aeroflot from Moscow to Dublin in the middle of winter! What could go possibly go wrong? http://en.wikipedia.org/wiki/Aeroflot_accidents_and_incidents
     
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  3. Given that you ride a VTR250 I'm assuming that you're relatively inexperienced (apologies if I'm wrong). To be honest, I very much doubt if an inexperienced rider would be affected by any difference made by a change of one tyre size. You might well be able to pick a difference in how the bike "feels" but any change to grip and ground clearance will be so marginal as to be irrelevant to you.

    Much is made of having a matched pair of manufacturer recommended tyres these days. I agree they're a nice thing to have. Now that I have a decent, regular income I try to stick to the maxim myself. But back in my poverty stricken days, tyres were whatever was on the secondhand shelf at my local wreckers that I might be able to squeeze onto my rims. Given that I rode a variety of quite odd machinery at the time, those rims were sometimes peculiar sizes too. MZ in particular loved putting weird rim width/diameter combinations on their bikes.

    Anyway, bottom line was that I frequently deviated from manufacturers recommendations but, as long as I kept the rear wider (or same width) than the front and didn't use a radial front with a crossply rear (not that the opportunity ever arose) I never found a combination that I would have classed as in any way hazardous due to the sizes. Utter lack of grip from ancient rubber or dodgy NoNamo makers yes. Handling weirdness from mismatched sizes no.

    In short, you almost certainly won't die as a result of what you propose. You may not even notice.

    That said, the VTR ain't that uncommon. Surely someone does an appropriate rear.
     
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  4. I reckon that if the advantages outweighed the disadvantages, Honda probably would've done it in the first place.
     
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  5. 140/70 vs 150/60 on the same size rim.....hardly any difference.

    A VTR250 is such a dynamic razor sharp good handling bike you are really going to be able to tell the difference ( NOT ).

    Do yourself a favour and change the front at the same time so that you have a matched pair of tyres..

    BTW Honda would have probably chosen the smaller tyre in order to save 25 cents on the bill of materials building the bike.
     
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  6. Wait a sec gentleman. Do you mean to say that my '07 Honda VTR250 is not the supreme pinnacle of superbike performance, speed, handling and engineering?... I feel jibbed.. But as I'm constantly telling myself, it's not how big it is, it's how you use it..

    Pot shots at my learner lap-rocket aside. It was my thinking too that as its not a high performance bike tuned in a specific way its not going to kill me when i put this tyre on. And The convenience of being able to purchase some decent rubber for the old girl is going to only add to my 2 wheeled existence and not take anything away. Correct?
     
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  7. Don't take it so personally. I think the answer to your question is 'give it a go - there won't be much difference'

    But if it was me I would stick to buying decent rubber of the size recommended by the manufacturer.

    Cheers
     
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  8. You will never know unless you try it will you.
    I'm running a 140 rear on my 250 kwaka (130 stock) and I like it.
    Could be better tyre, could be wider is better, could be all in my head.
     
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  9. Ahh I think Dan has confirmed my belief. Thanks for your advice gents, still learning, always learning, so I try and soak up as much as possible. I'll order the tyres off eBay and let you know how I go! Cheers guys..
     
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  10. ...... of course Honda's R&D department, with a budget equal to that of a small African nation, wouldn't have tested and decided what the optimum size is for the rear tyre on the VTR-250, would they? ....
     
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  11. Typically a wider rear tyre will slow down your steering a little.

    Extra grip is more down to the profile of the tyre than the width, but there probably won't be a whole lot of difference either way.
     
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  12. Given some of the horrors that Honda's (and every other manufacture's, come to that) R&D department have visited upon the motorcycling public over the years, I'm not sure if I have quite the same level of blind faith in them that you do :D.
     
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  13. When the R&D dept has their say, then its the bean counters that finish the job completely.

    That said R&D budget is probably spent in order of importance...ie...

    #1 Casey's bike
    #2 Where to fit the stereo on a leadwing
    #3 premium sports bikes
    #4 premium mx bikes
    .
    .
    .
    #2999...what size tyres to fit to a vtr250, knowing the rim came from a model xyz, and that had a XXX/XX-XX tyre
     
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  14. They changed from a 180 kph tyre to a 210 kph at the same time as getting rid of the 6th gear. Selling into markets with steeper and longer hills??
     
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  15. Lots of opinions, few facts.

    I think you could go to the 150/60 without drama. You may or may not notice a slight difference in handling and feel, in what I'd call steering response. You may find the bike needs a little more effort to hold down, compared to the 140/70 when it was new, or the effect could be too subtle for you to notice. Changes in the absolute outright grip available or the top speed of the bike are likely to be very small and not very relevant. You may find that with the wider tyre, you get very slightly better tyre wear, but the handling of the bike doesn't feel quite as good as it once was.

    It might pay to check that you actually have about 6 ~ 7mm or more between the chain and the edge of your current tyre, because if you have less, then a wider tyre may rub on the chain, and that isn't good.
     
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  16. if the rear rim is narrower than 4 inches wide i would not recommend a 150/60.
     
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  17. Haha I can see the opinions on this topic are many and varied. Who is right? We'll soon find out..

    A general consensus with motorcycle riding is that your own personal comfort and overall happiness with your bike is usually the most important factor. I know my bike is not quite on par with Casey's steed however she does the job at the moment and I felt like getting some decent rubber for her.

    In terms of convenience, price and ease of purchase the Internet was a good option and as long as purchasing this tyre was not going to endanger my life or make my bike unrideable, I thought I'd take the plunge.

    Either way the transaction has been done an the tyres are on their way. Once they get in and I get a look at them I'll report back and let you fellas know. Who knows though... Maybe I might be on-selling a cheap pair of tyres! Like I said. We'll see how we go..
     
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  18. You CAN put a car tyre on the rear of a Rocket III if you want to, but the questions is... why WOULD you ?!
     
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  19. Hornet as true as this is, marketing and cost placement of different models also have a bearing on componets used on specific models...
    Cost difference on the tyres themselves would be nothing but together with other componets make a big difference to the end price they can offer on a bike and have it compete against other manufacturers..

    I would stick to whatever the sizes are recommended for the rim/bike you have.
    In most cases there are more than one size available.
     
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  20. even though a 150/60 would fit fine on a 4 inch rim (i run a 150 on a 4.25 rim) i think you wouldnt get the full benefit as the bike would drag the footpegs well before you got to the edge of the tyre.

    this is what a 150/60 looks like on a 4.25 inch rim, its a little too flat shaped for my liking but for the street its ok. the shape the tyre is will depend on what tyre it is as they are all very different. yes i know i have not enough rebound damping in this photo :)

    [​IMG]
     
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