Tires, Offset, Scrub Radius & Minus Sizing

Discussion in 'Clarity' started by Lowell_Greenberg, Nov 28, 2019.

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  1. Lowell_Greenberg

    Lowell_Greenberg Active Member

    When minus sizing for winter tires on the Clarity- due to more limited availability of 50 mm offset tires- many will get tires with smaller offsets. For example, going to 215-55-17 and 7 inch rims, wheel offsets of 38-45 are more typical.

    Reducing the wheel offset, increases the scrub radius and this will have an impact on the car's handling. In addition, if you go alloy, the rims will be lighter, also effecting handling.

    Further the effect of the above on handling should be noticable and varies by car model- with as little as a 5mm change having an impact.

    Potentially changing scrub radius may also contribute to suspension wear. So if you do reduce the offset, the less the change, the better. Some advise staying within 5mm.

    This is what I have concluded:

    1. The discount tire houses usually make reasonable recommendations as to fitment- but they often ignore offset.

    2. Car manuals usually state not to change any spec from OEM.

    3. Changing offset by as little as 5mm will be noticed.

    4. The benefit of a narrower tire on snow grip, particularly on a low clearance car like the Clarity, is probably minimal.

    5. Rim load capacity is tied to GAWR. It is often hard to find what the rim is rated at- but most decent passenger rims should be OK for the heavier Clarity. Rim load capacity should be 1500 or above.

    So the devil is in the details. A 5mm or less offset change due to minus sizing, will probably not too negatively impact handling or suspension wear- provided fitment is correct. However, if expense is not an issue, sticking with OEM specs would probably be better. I am not certain the narrower tire width would make much of a difference in snow traction.

    As for the discount tire houses- not impressed based on recent experiences. Front desk staff are OK- but my guess is their service staff are pressured to quickly turn over cars. Incorrect tire inflation, torque and balancing seem all to common. And the aforementioned allhave the effect of bringing you back sooner for new tires- or worse.

    Sent from my SM-G975U using Tapatalk
     
    KentuckyKen likes this.
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