Ibike Newton and MTB ?

[smitsone]

Hello all,
Just wondering if anyone has used the newton in the mtb environment. Specifically for xc and marathon racing. Just wondering how the unit and it's internals would hold up in a rougher envionment ?

[jazclrint]

Glad I'm not the only one who gets crickets when they use those three nasty letters. Oh well. My Gen III iSport has held up fine. I am hoping the Newton does the same.

[Ratman]

No, we mtb'ers are out here, but, technical challenges acknowledged, Velocomp simply doesn't have an interest in developing a product for the mountain biking market, I'm afraid.

[jazclrint]

And that is fair enough. It's just a change I find odd. When I asked if the iSport could hold up to MTBing it was an emphatic yes. Now, its just the silent treatment.

Also, I'm out there beating the iBike drum in my shop and MTB club. And as we can see as evidenced on DCRainmaker it is an up hill battle. Got a guy in the road club who owned a Gen II and it left a sour taste in his mouth. And then to see someone else with a simple question get nothing but silence is deflating.

I feel like if they just made us MTBers sign some disclaimer saying that we promise not to bitch about things they can't control maybe they could get back in the business of making not a mountain bike specific product, but back to making a mountain biker friendly product. I feel like the altitude accuracy alone would be worth something. Not to mention pairing it with a dfpm and some setup from someone clever could net you some very serious and eye opening data on what products are more efficient, and where. And with all the memory available now some ant+ shock travel sensors could be some suspension guys fantasy come true. But now I'm getting carried away.

If they wanted to turn MTBer's heads all they would have to do is sponsor a test of who's sus design was the most efficient. Paired with a dfpm it seems to this simpleton that it would be very possible. Someone would just have to come up with the right settings to put into the iBike, and the bikes would have to have the same build and I'd say use one set of tires and wheels for the whole test. We'll let someone else decide if 27.5 or 29ers get tested.

If you could figure out how to let people know which suspension settings were the best you could sell the things by the truck load to the kids on Pink Bike.

[Velocomp]

No, we mtb'ers are out here, but, technical challenges acknowledged, Velocomp simply doesn't have an interest in developing a product for the mountain biking market, I'm afraid.

Really? We hadn't heard that.

Maybe we should stop working on some of the stuff we are doing right now.

[jazclrint]

No, we mtb'ers are out here, but, technical challenges acknowledged, Velocomp simply doesn't have an interest in developing a product for the mountain biking market, I'm afraid.

Really? We hadn't heard that.

Maybe we should stop working on some of the stuff we are doing right now.

Don't make my mtb cry man. It's not pretty.

[jazclrint]

Alright, I really hope some of the stuff you "are working on right now", is firmware and not hardware related (special mounts excluded) because I just pulled the trigger on a new Newton Powerstroke 5. I saw the coupon code on Facebook. Maybe I could have leveraged things to help make my shop a dealer and got a slightly better deal. But I am "upgrading" my iSport, and while my boss is a little more open to being an iBike dealer than anything else I suggest (and it would have been my money), the savings on the site was so good that the extra bit of cash seemed worth the piece of mind over trying to work out a deal thru my shop.

Although, where I am gone for 5 weeks at a time out to sea for work, I might be willing to trade leaving my new Newton with the local road club officers and my shop for demo use in trade for being a beta tester for any mtb specific updates.

[Ratman]

"Really? We hadn't heard that."

Until now, none of us have heard anything, either. Why should disbelief be surprising?

[Velocomp]

"Really? We hadn't heard that."

Until now, none of us have heard anything, either. Why should disbelief be surprising?

Well, most of the new things we've done we haven't talked about prior to their introduction. That would spoil the fun.

[Ratman]

"Really? We hadn't heard that."

Until now, none of us have heard anything, either. Why should disbelief be surprising?

Well, most of the new things we've done we haven't talked about prior to their introduction. That would spoil the fun.

Ok -- then I'm sure we'll all be looking forward to the "fun" that's forthcoming!

[bobbyperry]

yep. my wife and i use on mtb with the out front mount. we have not raced with them but do most of our training on dirt roads/climbs. all good

[ronpei]

I am thinking of installing my newton on myfat bike. Anyone else try it and if so any issues with low temperatures?

[Velocomp]

There should be no issues with low temperatures.

If using Newton with a fat bike, use Isaac to set your wheel circumference properly and also set Crr to 0.008.

[bobbyperry]

so what is the crr? why and how do you know to set t 0.008? what should it be on my 27.5 mtb with 2.1 tyres?

[ronpei]

Thanks for the crr tip John! That was one thing I was wondering.

[Velocomp]

so what is the crr? why and how do you know to set t 0.008? what should it be on my 27.5 mtb with 2.1 tyres?

Crr is coefficient of rolling resistance. It is a parameter that you can set while using the "Device/Setup Newton..." wizard.

[nsidirop]

There should be no issues with low temperatures.

If using Newton with a fat bike, use Isaac to set your wheel circumference properly and also set Crr to 0.008.

John, could you elaborate a bit about where the Crr=0.008 comes from? Isn't the Crr depending on both tire type, dimensions and the road conditions?
I ride mostly on All Mountain trails with my MTB. For Cal ride I rode on a gravel road and then whent to Device Set up in Isaac and chose the roughest road condition option. That ended up with a profile of Crr 0.0211 and Fric of 19.711
I have 27.5 wheels with 2.4' tires. I chose the "Keep accuracy of" option in the end of the set up.
Then I went to Edit Profiles and manually entered the weight figures and Tire circumference and kept the Aero scaling from the Cal ride.

Did I do it the correct way or should i manually change the profile by holding the Tilt angle and adjusting the Crr to 0.008 (or something else) in the Edit Profile window?

[bobbyperry]

mmmm yep thats my method with our mtbs. what with this 0.008 crr ????

[Velocomp]

Oops, my bad. I did not know Travis had already changed this one...

[nsidirop]

So the method I described is the correct one (Crr=0.0211 from Isaac / Device Set up) ?

[Ratman]

I recently performed a Newton5 calibration ride on Specialized Fatboy through a process much like that described by "nsidrop." The resulting profile produced an identical Crr of 0.0211. From a mathematical standpoint, it seems rather ironic (suspicious?) that the same value was produced in these two instances. But, aside from this "irony," the general magnitude of the estimate is plausible as the Analytic Cycling website estimates a Crr of .008 as typical of a "rough, but paved road." The trails I ride are frequently far rockier than any paved road that I've seen, and the tires (Surly "Bud" front and "Lou" back) I'm using are 4.8" wide with large, 7mm knobs, and inflated to only 5 psi. They're for maximal traction and bump absorption, not for low rolling resistance, so one would expect a Crr value far greater than that estimated for a "rough, but paved road." Using the Issac analysis tools, I've also had a Crr of 0.0173 recommended. To be clear, to minimize the known concerns regarding attempted calibration of the Newton on a very rough surface, the cal ride I performed was on one of the more "tame" trails in my area, characterized much better as "dirt" as opposed to "rocky." Also, I'm using a Newton Solo Front Mount which has been rock solid since installation.

During rides, I notice that I often see 0 watts displayed unless I'm going distinctly uphill or noticeably accelerating. On flat portions of the rides, despite the fact that I can feel clear resistance to my pedaling (i.e., I'm not coasting or freewheeling), the Newton still displays 0 watts. When I return home to analyze the ride file, the Newton reports that my original Crr has been converted to -.0192 (or a similar negative value)! Actually, the "Tweek Cda, Crr, & Cm" feature says that both the "Before" and "After" Crrs = -.0192 despite that fact that I've been trying to correct this problem by sending my Newton a profile with plausible Crr values of 0.0211 or 0.0173 immediately before each ride. Under these circumstances, the wattage, calorie burn and related values all appear to be low. When I edit the Crr values post-ride to one of the "plausible" values suggested by the cal ride files, the power data looks far more plausible, too.

As things now stand, the data produced during my rides is disappointingly low and obviously misrepresenting the effort I'm putting forth. I'm fully aware of the need to temper expectations with regard to use of the Newton on mountain bikes. Yet, other than the Newton changing my Crr to a negative value during rides, it seems to be doing a reasonably good job -- accurate enough for my needs. What's going on here? I've attached my most recent ride file below to allow a look "under the hood." Thanks.

2016_03_26_1241_11_Miles.ibr

(335.58 KiB) Downloaded 184 times

[Velocomp]

I'm not sure how you did your cal ride, but there definitely some issues in your profile, namely, a negative value of rolling resistance!

Here's what I recommend:

1) Use Isaac "Device/Setup Newton..." to reset the values of your profile

2) On the final step, select "Best Accuracy". This will initiate a 5 minute out-and-back cal ride.

3) Before starting your cal ride, lock up your front suspension fork. This will provide a correct result for tilt calibration

4) It's OK to do your cal ride on dirt.

5) when riding on uphills, make sure to lockout your suspension

You should be able to get good results.

[Ratman]

I'm not sure how you did your cal ride, but there definitely some issues in your profile, namely, a negative value of rolling resistance!

Here's what I recommend:

1) Use Isaac "Device/Setup Newton..." to reset the values of your profile

2) On the final step, select "Best Accuracy". This will initiate a 5 minute out-and-back cal ride.

3) Before starting your cal ride, lock up your front suspension fork. This will provide a correct result for tilt calibration

4) It's OK to do your cal ride on dirt.

5) when riding on uphills, make sure to lockout your suspension

You should be able to get good results.

I'd be happy to follow the instructions that you've provided, John, but I want to be sure that you understand what's happening. My profile always looks fine at home (has a positive Crr) before starting a ride. My Newton changes my Crr to a negative value during the ride -- this problem seems to have something to do with the on-bike processing that occurs while riding. If that isn't quite clear, please re-read my previous post for a more lengthy explanation (also includes a brief mention of the cal ride that I initially performed -- it wasn't that dissimilar to what you're recommending that I re-do). I've resent a new profile to the Newton with a positive Crr using the Issac tools numerous times (although I've not yet redone the cal ride as you suggest), and it always comes back with a negative Crr after the ride -- along with low power/calorie/etc values displayed during the ride.

Knowing this, do you still suggest simply redoing the cal ride? Also, in an attempt to help locate the source of this problem, I mentioned that "nsidrop's" cal ride derived Crr described earlier in this thread came up with exactly the same number as my cal ride. What are the chances that two completely different bikes (and mine is most probably the only fatbike) each ridden under unique cal ride conditions arriving at the exact same Crr (to all 3 digits)? It seems that this would be an extraordinarily unlikely event...or that there's something amiss in the calculation when relatively high Crrs are involved. My bike has an extremely inefficient tire configuration at the moment (traction, but also rolling resistance maximized), so you'd expect my Crr to be higher than 99+% of the riders out there. Your thoughts?

In the meantime, I'll re-do my cal ride as recommended and see if it corrects the negative Crrs. Thanks.

[Velocomp]

The issue may be that, somehow, your calibration data has been corrupted in your profile, forcing the negative Crr to compensate.

I'd do a new Device/Setup Newton..., followed by a Best Accuracy cal ride, to see if that fixes things.

[Ratman]

The issue may be that, somehow, your calibration data has been corrupted in your profile, forcing the negative Crr to compensate.

I'd do a new Device/Setup Newton..., followed by a Best Accuracy cal ride, to see if that fixes things.

I've just downloaded the files from my ride today. I began the day with a "Device/Setup Newton -> Best Accuracy Cal Ride" (done exactly as requested, with suspension locked out):

2016_03_27_1442_1_Miles_CalRide.ibr

(41.03 KiB) Downloaded 201 times

I followed the cal ride with a general ride (the trails had some rocks and roots, but could generally be categorized as smooth dirt trails with several long climbs):

2016_03_27_1452_8_Miles.ibr

(227.74 KiB) Downloaded 199 times

The data were closer to what one might expect as the new Crr was less negative, but it still is reported as a negative number, -0.0002. Other than the low-ish watts and calorie numbers, the remaining data seems to be correlating well with one another. Climbs are correlated with increased heart rates, lower wind values, higher watt production, and relatively steady cadence values; downhills are correlated with diminishing heart rates, higher wind values, significant coasting and braking, and zero cadence values.

Do the new ride files point to an explanation for the negative Crr number? Where do we go from here? Thanks!