August 26, 20169 yr If the tyres you've got on are some cheap knobbly MTB ones, then you might get better traction using a more road specific MTB tyre. Scwalbe Land Cruisers are a good compromise between road grip, loose surface bike path grip and price. http://www.wiggle.co.uk/schwalbe-land-cruiser-mtb-tyre-26/
August 26, 20169 yr Author Which size would be best for Big Bear rim? It came with 1.95 but this Land Cruiser doesn't come in that size. Sent from my iPhone using Tapatalk
August 26, 20169 yr Which size would be best for Big Bear rim? It came with 1.95 but this Land Cruiser doesn't come in that size. Sent from my iPhone using Tapatalk 26 x 2.0 will be fine
August 26, 20169 yr The Bear is fitted with 26" x 1.95" Kenda Kshield Try inflating to 30psi - lower pressure may help with traction. Schwalbe Land Cruiser 26" x 1.9/2" should fit https://www.evanscycles.com/schwalbe-land-cruiser-active-kevlar-guard-wired-26-commuter-tyre-EV204439 select 1.9/2" http://www.ebay.co.uk/itm/like/291360248510 £18.86 for two!!
August 26, 20169 yr If your bike came with 1.95 fitted then you should be able to fit at least up to 2.35" tyres, 2.1 or 2.25 are fairly standard sizing.
August 26, 20169 yr Author One other thought. Could the gears be removed from the rear wheel and put into the front wheel. Then the front wheel put into the rear? There seems to be enough distance between the dropouts? Sent from my iPhone using Tapatalk
August 26, 20169 yr One other thought. Could the gears be removed from the rear wheel and put into the front wheel. Then the front wheel put into the rear? There seems to be enough distance between the dropouts? Sent from my iPhone using Tapatalk No, that wouldn't be a viable option. Best bet is try to deal with traction issues on your current set-up, which I think can be minimized by fitting more suitable tyres.
August 26, 20169 yr just a thought for climbing steep hills with your Big Bear. The throttle overrides the asist and lets you control the bike more accurately. How about stop pedalling and climb more or less entirely on throttle?
August 26, 20169 yr Author The problem with these electric motors is you just can't get the wheel to turn slow enough. The minimum throttle speed just makes the wheel judder. Turn throttle a tiny bit more and wheel turns too fast and spins. Sent from my iPhone using Tapatalk
August 26, 20169 yr On gradients like that you need rear wheel drive, if it was a car you could reverse up! Even with rear wheel drive you will have to keep your weight on the front to keep the wheel on the ground. You can play with tyre width and compound all you want you will only improve the situation by a couple of percentage points.
August 27, 20169 yr The reason the tyre spins is that there isn't enough weight on it. It's nothing to do with tyres, throttles or anything else. To solve it, you have to bring some weight forward. When you're climbing a steep hill, the battery and all that junk on the rack will be behind the rear axle, which is very bad for this problem. You don't seem to be grasping that simple point. Move the battery forward and get rid of everything else on the rack. My riding mate has the 500w version of your motor on a bike with pulled back handlebars. It runs at about 28amps, so makes a lot more torque than yours. He has a 8kg battery on his rack, but it's tucked right up against his seat-post. He has no problem with traction. We ride up hills as steep as 30%, which is about as steep as hills go. Your battery is about a foot further back, which is not a good position for a heavy battery. Before the bars were changed. Also, note that it has heavier forks, which helps a lot. http://i451.photobucket.com/albums/qq236/d8veh/Bikes%20I%20Built/20140228_203133_zpsfda61a40.jpg
August 27, 20169 yr Author Before seeing your post d8veh i have this morning been moving the battery forward. The battery is right forward now, up to the seatpost and at an angle so all the weight is in front of the rear axle. Loooks a bit strange but if it works! Trials this afternoon. Sent from my iPhone using Tapatalk
August 27, 20169 yr Author http://uploads.tapatalk-cdn.com/20160827/438bc469c4a044b43f5403921f36bfe1.jpg Sent from my iPhone using Tapatalk
August 27, 20169 yr Author The battery could be moved even further forward by cutting the rack about a bit and bolting it to the crossbar. Flat and vertical. What do you think? Sent from my iPhone using Tapatalk
August 27, 20169 yr The more weight you can get on to the driving wheel the better. Do you know the actual angle and length of the steep part? You could set the bike up at the same angle with the front wheel on bathroom scales and measure the difference various mods make, then stick the scale under the rear wheel and see how much more grip you could have.
August 27, 20169 yr I know this may only help the tiniest amount, but you could try moving the seat forward along the rails, so there's more weight forward of the seat tube.
August 27, 20169 yr Author Moved battery forward as much as possible. Added a crossbar bag with some lead knitting machine weights in it. Added a heavy D-Lock. Been for a long hilly ride. What a difference it's made, no spin on the dry surface. I'm sure it's going to be better on a damp surface too. Thanks for all your responses on this thread. Very happy. PS. I am going to position the handlebars more forward tomorrow. Edited August 27, 20169 yr by Marwood Hill
August 27, 20169 yr Can you fit the battery on the front rack? If you move the bars forward you may be able to do as Fordulike says and move the saddle forwards. I don't know how much input you provide when climbing but be careful not to upset your riding position as this could have a negative impact on your input.
August 27, 20169 yr Author Different subject but may be useful to someone. My Big Bear is as quiet as a mouse.... I hate waitng for that next clunk going over those bumps. Firstly, i obviously moved and tightened anything loose. Removed my back pannier bags, they make a right din. The only thing left making a noise was chain slap. Chain tensioners are expensive but i found a cheap one called Brand X. Although it is excellent quality it gets poor reviews. Mainly due to fit and noisy. I overcome the noisy chattering of Brand X by fitting a nylon washer on the swivel joint. Perfect and my BB is absolutely silent on the biggest of bumps. See my photo above. Sent from my iPhone using Tapatalk Edited August 27, 20169 yr by Marwood Hill
August 27, 20169 yr Author Can you fit the battery on the front rack? If you move the bars forward you may be able to do as Fordulike says and move the saddle forwards. I don't know how much input you provide when climbing but be careful not to upset your riding position as this could have a negative impact on your input. The problem with a battery on the front rack would be the steering. It would need a different hefty rack which is not good on a bike with suspension forks. Also the cables would eventually break due to frequent bending. PS. Has a bike ever been made with the battery on the front? Sent from my iPhone using Tapatalk Edited August 27, 20169 yr by Marwood Hill
August 27, 20169 yr [ATTACH=full]15152[/ATTACH] Moved battery forward as much as possible. Added a crossbar bag with some lead knitting machine weights in it. Added a heavy D-Lock. Been for a long hilly ride. What a difference it's made, no spin on the dry surface. I'm sure it's going to be better on a damp surface too. Thanks for all your responses on this thread. Very happy. PS. I am going to position the handlebars more forward tomorrow. Having the handlebars that high won't be helping. In general, an upright riding position would have the bars level or a few inches higher than the saddle. Safety is another consideration, I doubt the stem is designed to work at that angle - there may be some markings on it indicating its range. Nothing may go wrong in steady road use, but on t'other hand the steering is the last thing you want to take a chance on.
August 27, 20169 yr I think your biggest problem is the handlebar position. If you correct that you can lose all the lead weights.
August 27, 20169 yr Author I think your biggest problem is the handlebar position. If you correct that you can lose all the lead weights. I shall put them back to my normal position tomorrow. Centre point directly above front axle.
August 27, 20169 yr Author I am thinking about ordering these. Very similar to ones fitted to Big Bear LS Edited August 27, 20169 yr by Marwood Hill
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