Best-laid plans

[EddiePJ]

Best-laid plans.

I’m currently completing a very short review of a Giant Full-E Plus 1 SX Pro, (more to follow on Monday) and last night was to be a ‘real world’ off road riding battery test, Yamaha PW-X against the Bosch CX. The idea was to complete a pre-planned 19 mile off road ride across very varied terrain, using Turbo mode on the Bosch CX and Sport mode on the Yamaha, as both supply a quoted 300% assist level.

Conditions were probably the worst that we had ridden for quite some time, and just 7 miles into the ride, both bikes were down to an indicated 50% battery capacity left!!! A shockingly poor range from both manufacturers. The Giant was also suffering very badly from chain suck, with the bike coming to an abrupt stop seemingly as soon as it got moving. It really didn’t like the high-power setting in such adverse conditions, and yes the clutch was engaged on the rear mech.The test was looking doomed already, and we still had 12 miles to go!

We sadly decided at this point that a high power setting battery test, just wasn’t going to work in such poor riding conditions, or at least if we wanted to complete the ride without having to walk. The decision was made to ride in the Eco setting on the Yamaha drive unit, and Tour on the Bosch drive unit. The Yamaha giving 100% assist and the Bosch 120%. Thankfully, the drop in power setting eliminated almost all of the chain suck issue that the Giant had been suffering, but problems were far from over, when I fell from the KTM and bent the rear mech hanger.
The ride consisted of some very short sharp climbs, that required a low gear ratio, especially now that the power settings were reduced, but it was the low range that was causing an issue, and the bike was having none of it. For each of these climbs, I had to switch to tour or eMTB mode, and use a higher gear than the conditions and terrain required. The battery level on the Bosch powered bike, was suddenly looking very questionable.

The ride continued with the bikes skidding and sliding everywhere, and sure enough at the 16.5 mile point, the Bosch battery died. Because of the nature of the test, I hadn’t wanted to take a chance, and so had a spare battery with me. The test was now well and truly over!
The Giant finished the 19 mile ride with 13% battery remaining, but had the rear mech on the Bosch powered bike not been bent, we both concluded that there was more than likely no noticeable difference in the performance between the two.

Noise was an interesting one though, as the Yamaha was definitely the louder of the two drive units. Although I suspect that it was more the tone or pitch that made it seem so. The Yamaha operated at a much lower deeper tone, which might well have made it seem louder than the high pitch tone of the Bosch drive unit.

The oddest thing of all, was just how muddy that the Giant was when compared to the KTM. I really have no answer to that one, but the KTM certainly returned from the ride pretty mud free.

Quite a failing in test terms, but still good to be out.

 

[flecc]

You are a mucky pup Eddie!

Those conditions are what horses are for.

For a change perhaps the larger chainwheel on the Giant's Yamaha wasn't so good in mud clogging conditions.
.

 

[soundwave]

if you had that motor it would have jammed solid with a cover over it.

 

[EddiePJ]

SW, the rocky Mountain is a complete design disaster for European off road riding conditions. I'd have left that laying in the first available ditch.

Flecc, I was actually very surprised by the chain suck issue, and I'd certainly like to next try the Shimano system for comparison.

Had the ride been completed in lower power settings, I suspect that the Yamaha system would of been fine. I really like it.

I'll complete my full review on Monday, but just as a note of comparison. I also completed a 19 mile on road ride with an elevation gain of 1,786ft ridden solely using the highest power setting which provides a quoted 360% of assist, and there was an indicated 42% of battery still remaining. I thought that was very good, especially as it also took one of the Strava top 100 climbs.

 

[EddiePJ]

You have to love a clean bike!

Wheels removed, cassette removed and cleaned, bake discs and pads cleaned with isopropyl alcohol, chain removed, cleaned and re-lubed, dielectric grease applied to battery contacts, anti seize compound added to seat post and Fork Juice applied, forks and rear shock thoroughly cleaned and Fork Juice applied, everything else thoroughly cleaned and checked with ACF50 applied to exposed threads.


I love bike maintenance and cleaning, as much as I do riding.

 

[flecc]

You have to love a clean bike!

I love bike maintenance and cleaning, as much as I do riding.

Beautiful.

Now it belongs on a plinth in the lounge.
.

 

[argoose]

The giant will clog with more mud than the KTM due to being a full suspension, with all the pivots and linkages being a mud trap against the clean BB area of the hardtail.
I had chain suck on my giant too, but changing to a 1x set up with a hope narrow wide chainring seems to have tamed it. Plus very rarely use Power mode, much prefer Normal

 

[EddiePJ]

Thankfully, other than when the rear mech clutch wasn't engaged, chain suck was never a problem on my full suspension KTM.

But you are right though, as there isn't a great deal of room around the chainstay area and linkages on the Giant. It is also running a 1x set up.

I'm pretty certain that it wouldn't take much to solve the problem, and I'd certainly not be dissuaded from buying one, just because of the above experience. The conditions truly were abnormal, and the high power setting did no favours either.

 

[The Bear]

dielectric grease applied to battery contacts

Good idea. Which type/brand do you use please as most I've seen is expensive.

 

[EddiePJ]

Hi Bear, I'm afraid that I don't know.

I have a relative that is a specialist engineer and every now and then, I scrounge some from him. Sorry that I can't be of more help to you.

I also use it inside of the heads/wells on exposed bolts. The quality of plating on factory supplied bolts is seemingly pretty poor these days, with them corroding with the first sign of mist in the air.

 

[georgehenry]

Killing a new fully charged 500Wh battery in 16 miles is pretty impressive.

That must have been the type of gluppy viscous sticky and treacherous mud that no one in their right mind would have attempted riding their bike through!

Knowing how much you like bike maintenance and cleaning I am beginning to wish you were a closer neighbor than you are.

I was slightly surprised that the Bosch CX used up its battery more quickly than the Yamaha although my Yamaha is the cheaper PW one.

I wonder if the new active line Bosch motor with less power might be a good option for a fitter or more active electric mountain bike rider who would appreciate the greater range of a less power hungry motor.

I know that after getting over the "how fast will it go" initial full power blasts when I first got my bike, I now ride off road in eco for up gradients and off for down all the time with only the most occasional dab of standard to overcome an obstacle without stopping.

 

[EddiePJ]

Killing a new fully charged 500Wh battery in 16 miles is pretty impressive.

I was slightly surprised that the Bosch CX used up its battery more quickly than the Yamaha although my Yamaha is the cheaper PW one.

The good thing about the first 7 miles of the test, was that both bikes were on a comparatively level playing field, and both used 50% of their fully charged batteries. Even the Bosch battery had only received three full charges from new. Both power settings were also 300% assist.

Sadly the test failed after that, when we had to switch down modes to Eco on the Yamaha which gave 100% assist, and Tour on the Bosch giving 120%
These were the two closest settings, as Eco on the Bosch system gives just 50% assist.
So the Bosch was giving an extra 20% of assist, but I also need to use eMTB mode for several of the climbs, due to the bent rear mech hanger and not being able to use the lower gear ratios. Had this not been the case, I suspect that the result would have been quite even. I had actually expected the Yamaha drive unit and battery to have out performed the Bosch system by quite some margin in respect of the battery, but it wasn't the case.

It would be good to repeat the test in drier conditions, and with a spare battery for each bike. Sport on the Yamaha and Turbo on the Bosch system, were the only matching power settings at 300% assist.

Like you, I hardly ever use the higher power setting under normal use, and being truthful, preferred the spread of assist levels with the Yamaha system. I still do not like eMTB mode.

Another observation in respect of the batteries, was that the Bosch system when down to an indicated two bars of battery capacity remaining, drops very rapidly, and shuts off with no warning, where as the Yamaha system didn't.

 

[Gringo]

I wonder if the new active line Bosch motor with less power might be a good option for a fitter or more active electric mountain bike rider who would appreciate the greater range of a less power hungry motor.

I would say it was designed with you in mind, free running off power and enough power for light trails and bridalways.

A combination of the manufactures description of the new motor and my positive experience with the earlier variant was enough for me to order the cube acid one ( gen 3 Bosch motor )