Puzzled by pawls

[billwarwick]

Have just got bike back from lbs. forks needed a service ( turns out they were full of muddy water and crap) and also had a problem with what felt like gears were slipping when put under sudden load or climbing . Not being technically minded, I thought that the gears just needed adjusting. Anyway, the guy says the problem is the pawls in rear hub are not man enough for the job. I didn’t even know that they existed. He says best solution would be to buy a better quality wheel which has 4 pawls as mine only has 2. Bike is an entry level Haibike so it figures that not all components are going to be top notch, and the bike does get a fair bit of abuse.
My questions are....
Is he talking sense?
How do I choose the right wheel?
How do I know how many pawls a new wheel would have?
Why is life so complicated?

 

[Eckythump]

Not sure 4 pawls will help as normally only two engage at a time. The extra pawls are used to increase the number of engagement points as they are offset from each other.

 

[DAZ1925]

I thought only I9 hubs had only half the teeth engage at a time (they have six that work in three's).

Usually more pawls gives a stronger engagement, you might just have dirt in the freehub stopping the pawls engaging correctly. you could try stretching the springs to give them more force when pushing the pawls out. The issue is they are very small components and are easily lost.

Choosing the right wheel? not sure what you mean is it 650b or 29er, boost or non boost, 12mm axle, Internal rim width? The easiest way to upgrade is look at the wheels the more expensive models of your bike have. Hope, Chris King, and Industry 9 hubs are probably the best out there in my opinion.

How do I know how many pawls a new wheel would have? Look at the specs on the manufacturers site.

Why is life so complicated? It's not, they are all industry standard, lol

 

[DAZ1925]

One other thing I neglected to mention, Sram or Shimano cassette?

 

[Eckythump]

I thought only I9 hubs had only half the teeth engage at a time (they have six that work in three's).

Only Hope hub I have is a Pro2 trial hub. That hub only engages 2 pawls at a time. Apparently it differs from the regular hub.

My mistake

 

[highpeakrider]

Do you know which make hub it is and rim, it might be an option just to have a new hub rather than new wheel. If it was fine in the past might just need the free hub cleaning and a bit of grease.

 

[DAZ1925]

Only Hope hub I have is a Pro2 trial hub. That hub only engages 2 pawls at a time. Apparently it differs from the regular hub.

My mistake

I never knew that, everyday is a school day

 

[billwarwick]

cassette is sram, wheel is 27.5 generic Haibike. lbs have done all they can with it, but it still slips. if I just swap out the hub, is it a job that I can do myself or does it need special tools?

 

[Markymark]

I've got the Haibike sduro fullseven LT4.0 which I guess is the entry level full susser but would imagine it has similar components. I've only had the bike a couple of months but never had it feel like anything is slipping on mine. are you sure it's the pawls slipping?

 

[Gary]

the guy says the problem is the pawls in rear hub are not man enough for the job.

Er.. what? Not man enough in what way? Each pawl is simply a shaped piece of hardened metal that opens and closes to engage with a ratchet when drive is engaged or the hub freewheels forwards. usually hinged and combined with a spring.

lbs have done all they can with it, but it still slips.

What have they actually done though?
Were the pawls or ratchet damaged/worn at all? And did they replace the damaged parts?
Did they replace anything?
A pawl and ratchet is very basic/simple mechanical system. There's actually not all that much t]o go wrong and often if pawls are failing to engage it's something as simple as the springs not having enough force to engage the pawl or too much grease stopping them doing their job properly. if it's the springs they can be carefully stretched out to create higher tension in the pawls. if it's the grease, remove it and replace with something far lighter or even an oil

 

[Tamas]

+1 for proper cleaning and lubrication with light grease or oil. The two pawl designs usually have the circlip style spring and if lubricated with sticky grease it might not have enough strength to engage the pawls fully and they can slip. If the pawls are worn a replacement pawl/spring kit is ~10€. I would definitely go through on these steps before spending on a new hub or wheel.

On the other hand, if you don't like the slow engagement hub (it's probably not more than 20T) then it can be a good excuse to upgrade it to something faster.

 

[steve_sordy]

I had an e13 hub with really bad seals. Water would get in and the springs would rust, then it was game over! I suspect it was a dodgy design from day one. The UK agent repaired the freehub FOC twice and said that they had never had to repair a hub more than once. Then it failed a third time, so they replaced the hub, the bearings, new design seals, the lot. That fixed it. I had bought an e13 wheelset because it came with a five-year warranty. I thought that showed their confidence in the product, misplaced as it would appear.

 

[Gary]

I had an e13 hub with really bad seals.

Yeah. I'm fairly sure E13 revised their seal design on their hubs..
I've always found them to be very very helpful guys and eager to keep customers happy without further outlay (Fairly sure you'll know what i'm getting at). Unfortuanately they don't really know what UK conditions are like. I had this discussion many years back with Dave Weagle in the early days as his EVEL and then E13 guides would clog in UK downhill conditions. For all his expertise and Engineering background he had absolutely no idea that what I was describing could even happen nevermind be a real issue. Shame the UK part of the company is just a distributor reather than the product design base.

 

[Gary]

On the other hand, if you don't like the slow engagement hub (it's probably not more than 20T) then it can be a good excuse to upgrade it to something faster.

Something with higher engagement definitely makes more sense on an Ebike with a freewheel in the crank/motor as well as at the hub

 

[billwarwick]

thanks for replies folks. lbs did not replace anything but did something with springs and lubricated and said it would slowly get worse so I think I am going to look at upgrading the wheel as being a cheaper bike, it could probably do with a few quid spending on it. Thanks again.

 

[MattyB]

Before you do that I would encourage you to take apart your freehub and take a look yourself, or at the very least get a second opinion from another bike shop. It does not sound like they are necessarily giving you the best advice...

 

[Tamas]

Something with higher engagement definitely makes more sense on an Ebike with a freewheel in the crank/motor as well as at the hub

My Meta came with a 20T Formula hub and I couldn't stand it as my other wheelsets are between 36 and 52T. I was debating between DT350 and Hope Pro 4 and went with the Hope because flange distances and BCD's were almost identical and I could use the same spokes.

I think for some people - depending on riding style - slow engagement is not that noticeable. Opposed to Shimano's instant engagement, my wife's Yamaha PW has a slow 16T freewheel in the motor + the rear hub. It adds up and it could be very annoying on the trails but it's a trekking bike so it doesn't matter...

 

[billwarwick]

I’m going with your advice, Matty. Got a lot of time over Christmas and it will give me something to do and I might learn something. If anyone wants a bag of assorted springs,washers, ball bearings and pawls in January, just let me know

 

[Stumpy]

I’m going with your advice, Matty. Got a lot of time over Christmas and it will give me something to do and I might learn something. If anyone wants a bag of assorted springs,washers, ball bearings and pawls in January, just let me know

Good luck and well done for trying ?? If it all goes tits up you won’t be short on here of friendly folk to help!

 

[MattyB]

My Meta came with a 20T Formula hub and I couldn't stand it as my other wheelsets are between 36 and 52T. I was debating between DT350 and Hope Pro 4 and went with the Hope because flange distances and BCD's were almost identical and I could use the same spokes.

I think for some people - depending on riding style - slow engagement is not that noticeable. Opposed to Shimano's instant engagement, my wife's Yamaha PW has a slow 16T freewheel in the motor + the rear hub. It adds up and it could be very annoying on the trails but it's a trekking bike so it doesn't matter...

So on that bike roughly what angle would your pedals need to go through before you get engagement? Are we talking double digit degrees?

 

[MattyB]

I’m going with your advice, Matty. Got a lot of time over Christmas and it will give me something to do and I might learn something. If anyone wants a bag of assorted springs,washers, ball bearings and pawls in January, just let me know

Great stuff - let us know what you find. Just remember to lay out the parts in sequential order as they come out on some shop towel, and take lots of pictures as you go so you can put it back together again in the right order after cleaning and relubricating.

 

[galaga187]

If your pawls/springs do fail to engage when you are out riding you can sometimes get them to engage by bouncing the back wheel to free them (worked for me on shimano 11-32 Ultregra road bike cassette).

 

[Tamas]

So on that bike roughly what angle would your pedals need to go tgrouch before you get engagement? Are we talking double digit degrees?

Well, the 16T freewheel on the motor is already 22,5 degrees. The rear hub is ~18-24T (I'll have to check it) and at the pedal, it depends on which gear is selected. In the lowest, the gear ratio is 1:1 (36/36) so in the worst case scenario, it can be ~40 degrees. It looks big on 'paper' but on a trekking bike, it's a non-issue.