Maximum cornering: theoretical

[ThunderGuts]

Morning all,

The other weekend I did a ride out with a friend; I was on my basic and elderly ER5 and he was on a modern BMW S1000XR. Clearly his bike was significantly more advanced than mine, but nevertheless we had a great ride out and at the end he remarked about how despite the ER5 being such a basic bike, it still did everything that day his did. We then got talking about cornering capacity. Now, I know there are a lot of variables on this so let's just set a few things straight first;

- Assume both bikes have the same rubber compound (tyres are obviously different sizes though)
- Assume the test area is perfectly flat with no undulations/ripples or surface imperfections
- Assume both bikes are being ridden by the closest thing to a computer, i.e. perfectly consistent rider with no errors

With these things in mind, which bike is likely to ultimately be able to corner harder? Instinctively I'd think the BMW given it's broader tyres, sportier setup etc., but I'm not so sure it's quite as simple as that?

Clearly if you throw in real world issues, like an undulating road surface, I'm sure the advanced suspension on the BMW is going to give it an advantage on top of any others it already has.

Just an interesting topic for discussion; what do people think?
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TG.

[pompousporcup...]

the s1000 for sure.
chassis development, steering geometry, tyre profiles(because of the size) and computer aids are going to help the newer bike out handle and out corner the er5..

that said. i was consistently being overtaken into and out of corners by pesky er5/cb500s at cadwell, bikes that had half the cc and were much older than the one i was riding.

[ThunderGuts]

[chris-red]

Beemer because of ground clearance.
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[ThunderGuts]

Yeah I could imagine that being an issue actually! The absence of one of my hero pegs suggests that the previous owner discovered that too (or managed to knock it off during one of it's drops).
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TG.

[Sister Sledge]

I'm not clued-up on the suspension. Do they have computer aided stuff in the shocks on those? Just that I think it would go a long way towards keeping rubber touching the surface and thus having enough grip.

I must be going back many decades here but I once watched a race at Langbaurgh race track at Middlesbrough.

https://www.teessideautodrome.co.uk/

It was between 250cc bikes. The race was on the kart track and wasn't a long lap but did include some 'interesting' corners.
In the race the majority of bikes were 250lcs but one stood out - an old CZ 250 with the square tank, mega finned air cooled engine etc. The CZ won the race!!
The reason was more about power delivery than anything else and half those lcs fell off in their attempts to outrun the CZ. That CZ had a smooth power delivery and not a peaky tuned engine.
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[ThunderGuts]

[Kawasaki Jimbo]

[Jim Mc]

[G]

Given it's perfectly flat and you're looking for consistent cornering speed ( I presume), suspension isn't going to come into it too much. If you're talking a fairly quick turn in and getting on the power again, better suspension will make a difference.

Ground clearance may well be an issue as mentioned - though hanging off decently can mitigate this.

The bigger tyres will allow the BMW to 'key' with more surface, but it's also got more weight to keep on track.

[DJP]

All else being equal, on a perfectly smooth track, the greatest cornering ability would belong to the bike with the most ground clearance.
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[G]

[redeem ouzzer]

The ER5 has a steel frame, damper rod forks and crossply tyres. These are not things conducive to fast cornering.
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[stevo as b4]

Lots of theoretical bollocks.

You and your mate with the BMW are never going to be equal riders of the same exact ability, skill, and confidence no matter what you both do.

As you and I know, theoretical doesn't mean naff all out in the real world, and there's no theoretical perfect or flat roads and exact constant radius and road surface friction bends anywhere on the highway either.

Therefore it's down to the rider. If BMW rider isn't very good but the ER5 rider is fast, smooth and confident, then who do you think will corner the quickest?

If the slowest rider is on the slowest bike, then again it's pretty obvious where that's ending up too.

[ThatDippyTwat]

As said, it's largely down to the rider in most legal conditions in the UK. I regularly pass a mate that rides an '09 R1 on my '96 Viffer. That should never happen. I'm not a particularly fast rider these days either. But he's almost scared of corners, and makes it easy to nip up the inside, around the outside. He absolutely slaughters me on straights, he has something like 80HP more and 40KG less, but he's on the brakes so bloody early, I reckon I could probably take him on something like an RS125 or a Mito, let alone a VFR or any capable sportsbike. It doesn't matter what youre riding if you can't use it properly.
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[Bozzy.]

I’d imagine the BMW still being the more capable bike. I think you’d need to be on a track to really see a difference though, as riding on a public highway would still be the limiting factor.
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[MCN]

BMW.
Because of rules, laws and customs.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[recman]

Get yourself a Street Triple and take the piss out of him.

[ThunderGuts]

To be fair, he's both a more skilled and confident rider than I am and clearly real world riding is a whole different ball game - the whole discussion came up because I think we were ultimately getting to the basics of the physics, i.e. taking out all the variables (rubber, rider, surface, suspension) and just thinking about pure cornering physics and how much difference things like bike geometry, weight, centre of gravity etc.
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TG.

[MCN]

It is all related. If it wasn't then there probably would not be a demand for tyre, suspension, frame, brakes and geometry performance in bikes.

A more accurate test is maybe an ABS DTC bike against it's More basic sibling. With the same rider on the same course.

It is always 'opinion biased' when mates compare. Mostly.

Some say a 600 is faster around a track than a 1000.

It isn't but there are a lot of folk who are fast on any bike.

What a minefield subject with too many correct opinions.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Kawasaki Jimbo]

Just to note that the BMW S1000XR- that's the tall 'adventure sports' machine, not the road racer.

[TaffyTDM]

Also : who had the bigger hangover?

[Old Git Racing]

If I couldnt corner harder and faster in any circumstances on the beemer I'd give up riding.

OGR
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