Make and model of chassis
2006 margay brava 1.6 limo
I need help with
Im upgrading my older margay brava and I’m wondering if it would be worth the money to upgrade to metric mount wheels and 90mm hubs? Or should I save the money and just stick with DSM magnesium wheels? Im currently running aluminum wheels. This is for a senior yamaha can. Thanks
Make and model of chassis
I guess that depends on what you’re trying to achieve? I ran an Ignite with a World Formula last season that had DSM. I prefer a kart that the front end really digs in and no matter what I did I could not get the front end wide enough. I ended up throwing some 75mm front hubs on it and it definitely helped. The reason this was such an issue is because we are required to run a 7.10 rear tire, My thought is that DSM works better with a 6.50 rear tire.
How much would it cost? Off the cuff it sounds like a very nuanced change and the money might be better spent elsewhere.
Thanks for the replies! Well last weekend I raced and it was like being on ice in both the front and rear ends. Yes the tires were older but still have some life in them. The temp was about 40 degrees. I spun out about 7 times between practice and qualification, I made several adjustments and nothing worked so I withdrew from the race because I couldn’t get any grip. I noticed my competitors all had front hubs and most had 50mm rear axles. All the newer margay karts have 50 mm axles and 90mm front hubs with magnesium wheels. The cost for the wheels is $269 and the front hubs range from $40 to $60 a peice depending on size. I would like to have the extra grip and tunability especially since we will start racing in the rain next season. I race at the newly owned whiteland raceway park in Indiana. I could just save the money and buy a new kart but I love the one I have and I’ve put a lot of money and work into this year so it only makes since to put in a little more and get it competitive with the new models
We also run 450 front and 710 rear tires. Bridgestone ylc
This is a lot of money to spend on something that probably isn’t going to help your handling issues. First of all, 40 degrees obviously is pretty cold conditions so that’s the root of your lack of grip, but spinning 7 times isn’t the kart’s fault, that’s your right foot’s fault. Before throwing $400 at an older kart, I would spend a few bucks on some practice sessions in that weather to make sure you can make it around the track without spinning.
What adjustments did you try to get more grip? What tire pressures were you running?
I bumped the rear hubs in 1/4 of an inch each side and the fronts I moved them in one small spacer. I changed the tire pressures from 16 psi to 17 psi. When I went out it was way way worse than before. When I tried to turn it would just slide straight but it wasnt tight is was loose loose like on ice or driving in water
I just discovered that the top bolts that hold the bearings tight within the cassette were loose on both sides allowing the axle to slide about 3/16 to 1/4 of an inch on both sides. This may just be why I had no rear grip I guess in my haste to make qualifying I over looked them. But this still doesn’t explain my lack of front grip. I’ve never went into a corner and turnt the wheel and just went straight before. I’ve raced the kart since 2011 and never had this issue
Your problem is confusing? Usually if you don’t have front grip you don’t spin unless you’re locking up the brakes? Try dropping your tire pressure to 11-12 psi you might be loosing contact patch with the pressure that high. If your axle is moving side to side the kart is going to be completely unpredictable! Front hubs and mag wheels aren’t going to sort out these problems as TJ said spend the money on track time to sort the kart out and get some practice, that’s the thing that helps the stopwatch the most!
Narrowing the front track reduces front grip pre apex. Start by just shifting spacers inside and increasing front track first. If you haven’t max’d out on spacers then you definitely don’t need to spend on front hubs and new wheels yet.
Are the cassette pinch bolts loose or the grub screws that hold the axle in the bearings? If it’s the pinch bolts the axle shouldn’t move a 1/4” from side to side. I’d spend some time going through the kart and see if your dealing with other issues.
This sounds like some bigger issue. I mean at 40 degrees the kart is going to have no grip for a few laps, it’s going to feel like driving on ice. But if you’ve been driving it for 7 years and still spun out 7 times in practice I think something is maybe mechanically wrong with the kart. Check for cracks or bends.
It doesn’t really make sense that you’re mainly dealing with understeer but spinning out. Those are opposite issues.
Or “push/kick” maybe where the rear snaps once the front finds grip.
Yeah it was the pinch bolts, they were almost falling out of the cassettes. I’m in the process of totally gutting it right now! Do cassettes wear out over time?
Thanks TJ, I’m going to go over every nook and cranny to see if anything is cracked on the frame. I’m hoping it was just the loose cassette bolts. The kart was snappy loose in the middle to exit of the corners in practice. Then I made the adjustments and it became 10x worse that’s when it was like being on ice and I totally gave up for the day
It’s certainly possible if they were excessively loose and the bearings were moving around more than usual. Also, I would imagine in sand and dirt got in there, that would accelerate the process.
Thank you, I’m going to inspect them tonight after work
Worth noting, setting driving issues aside, that switching from DSM to hub mount, or from aluminum to magnesium wheels is not a small change – you will notice a difference, even in cold weather!
However, if you continue to spin a lot, you could have the best handling go kart or the worst handling go kart, it sounds like some more track time and coming in after each spin and breaking down why it happened is more vital, and overall more cost effective. It may be hard to do at first, but maybe chat with a local guy or gal that gets around the track pretty well. Often they like to talk about how they drive certain corners.
Thanks Eric! I’m probably going to get a set of mm magnesium wheels, I need a new set anyways since I’m going to need rain tires at the ready next season. The DSM and mm wheels are both $269 so I may as well make the switch. I appreciate everyone for the help thank you!
Slight (or not) tangent, if everyone doesn’t mind, what is the change going from mag to aluminium wheels of same size?
A guy I spoke to said that he preferred aluminium wheels as being more flexible and forgiving. He’s the only person I’ve spoken to that seems to even consider aluminium in the dry.