BD4 - The season so far

It would be fair to say that it has had its ups and downs. So far the chassis has proven to be tough but not indestructible, awesomely fast in its standard form but when it comes down to winning races then it's the man on the sticks that makes the real difference. We've proved its faster than anything but due to screw ups on the riders part we have yet to prove it's a winner

Both the teams bikes have been run as kit. Ian's has had a small amount of weight saving work (drilled holes in and milled out part of, the swing arm and front headstock mount) but the bikes have no other mods that cant just be bought from Nuova. At Wombwell Ian ran a slightly different steering system but reverted to the normal kit springs at Mendip.

At Wombwell the low grip meant that the BD4 chassis concept was slightly harder to ride than a kit bike. This is due to the bikes increased steering ability combined with its more forward weight bias. This results in it being harder to put the power down and thus pick the racing line into and out of the lower speed corners. However there is no arguing with its pace as Ian's was the fastest bike round the track all day with a fastest lap nearly 1 second quicker than any other bike (Steve Newey's) and 2 seconds quicker than anyone else. He should have won as well but struggled in the cold weather and although leading by miles at the half way point still managed to throw it away just at the end to a slower but faultless Steve Newey

At Mendip the bike again excelled with Ian circulating 2 seconds a lap faster than last years pole (which he also set with a modified Nuova bike) and was again a second a lap faster than Steve Newey with his highly modified Nuova bikes. Mark was also doing times that would have won him the race last year and was some 5 seconds a lap faster than he recorded last year. Again both bikes were basically kit Nuova bikes fitted with front brakes and the BD4 chassis. Ian should have won comfortably and Mark should have cruised to a minimum of third but once again it was the riders that failed to perform, depriving the chassis once again of its maiden win.

Steve currently has two bikes that he uses at each meet. They are essentially the same with the only significant difference being in the location of the C of G, and he switches between them based on the level of grip for each run. We may be wrong but it appears at the moment that he favours the higher C of G bike, but this may be down to technical difficulties on the day, we're not sure.

For comparison and to help any others that may wish to improve their bikes Steve's mods appear to include:-
" Complete front suspension / steering assembly is lowered by approximately 10mm
" Side hoops moved rearward to a similar position to those on BD4
" Steering servo mounted in its normal place (normal for a bike running a front brake!) but fitted with an extra long steering arm (note you will need a transmitter with a rate adjuster to run this)
" Brake servo is mounted lower down inside the chassis plates the exact location and mounting is unknown
" Steering springs as kit set at a length of approx 28mm.
" Rear swing arm in the lowest mounting holes.
" Rear damper is mounted in either the standard middle or front hole, although he has a lot of extra holes here so we may be wrong.
" Of the two bikes one has the batteries in a normal stick formation but with the front raised significantly to increase ground clearance and C of G. The second runs saddle packs with one saddle mounted conventionally under the motor the other between the chassis plates but inclined upwards at approx 30 deg for a further increase in the C of G and better ground clearance.
" The chassis side plates are significantly cut away to save weight and again increase ground clearance.
" Home made steering damper to reduce weight (carbon fibre) possibly others that we haven't seen as his bike does feel very light.
" Awesome front forks. Steve maintains that they are standard forks but if that's the case he is either very lucky or knows something about building them that we don't!
" We think he is running an uncut faring at the moment but he has in the past run fairing's which have been slimmed down in the middle again for added ground clearance.
" Significant effort has been put into lightening the bikes with everything that can be drilled out or cut down lightened (something we will be working on for our BD4's)

(Note that this is unofficial guide and we may have missed something or incorrectly described others)

Our calculations suggest that Steve's C of G is only approx 5mm lower than that of BD4 however of more significantly is that it is approx 10-12mm further back. This means that in low grip situations his set up probably has an advantage as the rearward bias helps with rear traction and the ability to put the power down. But as these bikes are just hard work and no fun when the grip drops off to much, such as in the rain, we are not that concerned. The added performance of our system in the dry more than warrants the change.

Conclusions…. Well not that many, it's too early to say. What is for sure is that you can't race to win with a kit, unmodified bike. The best example of a standard bike is the one used by Colin MacCabe who is running a Nuova with a front brake system but otherwise pretty much kit. Unfortunately he was 3-4 seconds!!!! off of the pace at Mendip, and he is a quick rider finishing third in last years championship. Now we all know that it's the rider that makes the biggest difference but it is currently unlikely that he will ever win a race, regardless of how well he rides.

BD4 is very quick, it turns better than a standard bike and if Ian and Mark ever learn to ride as well as Steve Newey then it will carry far more mid-corner speed and wont crash!.

Its strongly recommended that owners fit the Nuova rubber mounted wire crash bar supports as not only are they superb but they help absorb the impacts of violent high sides. One owner's chassis has so far broken a rear crash bar mounting lug because the bike had thicker, solid crash bars and the rider had a particularly nasty high side / crash (easily fixed though by just drilling a second hole slightly lower down). And Mark broke both the front body mounts off of one side in a flat out crash clipping a marshal point at Mendip, but it is unlikely that any bike would have survived this unscathed such was the impact.