BSOs: Bikesdirect Motobecane 300HT or Gravity Basecamp? Unboxed on pg. 2

[glennb]

Yes, with room to spare.

The big triangle and cylindrical tubes are major benefits, and the compromises should not be an issue in your application.

The bottom bracket area’s only really stressed by out of the saddle riding in big gears.

Skinny stays I’m not sure about. I’ve had bikes that suffered tire frame and fork rub leaning hard into corners, but they were boutique road bikes with tight clearances and super skinny stays/blades … and it was likely just the wheels flexing.

Skinny top tube I would expect to only be an issue with a loaded rear rack. Even five or six kilos on the rear and you’ll feel the tail wag with any sudden direction change. And a bike that does that is almost guaranteed to develop shimmy at some speed. IME around 30mph, but could be any speed.

I’ve no idea how the central battery affects things, whether it counteracts or contributes to shimmy. So, again, I’d want to test it with a dummy load rolling down a steep winding hill to see.

It is worth doing. Other than step through frames, the only bikes I’ve had that shimmied had long skinny top tubes.

 

[neptronix]

Thanks for your insight, glennb

I learned my lesson about rear racks long ago. Extremely bad idea, because even if you don't have frame issues, it's countering your steering motions ( bad news for handling )

Centrally located batteries are usually great, even if you have some slop in the mounting because it's in a frame bag.

You do make me think that this bike is ill suited for a large battery experiment. At least the battery would be sitting on what looks like the stronger area of the frame. The battery i'm eyeing is the 52v 23ah triangle from Grin that weighs 13lbs/6kg

I think it'll work out!

 

[marty]

One problem and this is serious. I hate Black and I hate White. Any other color would be good. Remove everything from frame. Get it sandblasted and powder coated. Powder coating guy has lots of colors. Ask him what colors he likes? Ask for supper glossy.

Powder coating is cheaper and more durable then paint.

What colors do you like?

Also I hate noise. Get more quiet tires. And the most quietest hub motor.

 

[marty]

frame bag

Would you put gasoline in a fabric bag? Batteries are dangerous the same. Batteries should be in a rigid case and mounted to frame so they don't get damaged if bike tips over or crashes.

 

[neptronix]

The madness continues.

BikeIsland says they shipped a few days ago... and it's too late for a refund or product switch.
Today, i hear the Gravity Basecamp is out of stock and have given me a refund.

Just ordered a new Yellow 21" Motobecane HT 300 for $299 from Bikesdirect.

Third try's the charm?


Well, i think the Motobecane is a lot closer to a bare minimum frame for an ebike anyway. These two pictures are not to scale, but you notice the thicker diameter of the bike's tubes leads to a much better join with the headtube. We also have a gusset. The difference in frontend strength is probably large. That's good.

The fork may also not be an immediate throwaway.

Motobecane HT 300 Frontend​ ​

Gravity Basecamp Frontend​

Here's some pictures of the two previous bikes i've owned and beat on at >= 36mph

Turner Burner - mid 1990's​

Trek 4500 - early 2000's​

From the view of the frontend, the Motobecane 300 HT looks like it might compare to the originally more expensive, but much older bikes i've owned. I'm hoping it's the budget king i was thinking it was. Let's see

 

[glennb]

That looks a lot better. Better than the Trek.

It’ll likely be half a pound heavier, but I can’t imagine that bothering you.

 

[neptronix]

Nah, 1-2lbs heavier is no big deal when i've got a net reduction of 5-7lbs over previous bikes
A much bigger factor is that the vehicle could benefit from the rider dropping 50lbs of covid-lockdown + new relationship weight

 

[calab]

I hate when the cable brake & shift cable mounts are located on the bottom of the top tube, when it comes to battery placement within the frames triangle when utilizing the top tube for mounting.

 

[99t4]

I hate when the cable brake & shift cable mounts are located on the bottom of the top tube, when it comes to battery placement within the frames triangle when utilizing the top tube for mounting.

Seems easy enough to rectify with retrofit clamp-on cable stops?

Cable Backstop

The clamp-on Backstops give your frame instant cable housing stops. We’ve got Backstops available for most frame sizes. Cable Backstop Instructions

problemsolversbike.com

Cable Stops - Clamp-on, for brake and derailer cable housings.

If your bike lacks housing stops or you wreched them beyond repair, here you go: Hinged, aluminum clamp-on stops that come in two sizes to fit over two different diameter tubes: 28.6mm (1-1/8") and 31.8mm (1-1/4"). There's only a 1/8-inch difference in those tube sizes. It's helpful to have a...

www.rivbike.com

Or just use full enclosed cable for that part of the run?

 

[calab]

Its an easy fix, just saying I dont like it. Its extra steps, another thing to think about when building a nice ride. It also depends on how your mounting them, for me I required a nice smooth surface but you could have offset aluminum mounts from Grin to mount your battery base plate or not.

 

[neptronix]

I hate when the cable brake & shift cable mounts are located on the bottom of the top tube, when it comes to battery placement within the frames triangle when utilizing the top tube for mounting.

Dang, i didn't even think about that.

Luckily the cables are on top on the Motobecane, like my 2000's Trek.
That's worth an additional 1/3rd of an inch forward. I like it

 

[neptronix]

It appears to have shipped. I should have it saturday.
Shipped weight is listed as 39lbs on fedex.

 

[neptronix]

So both the bikes arrived today. I was mad that the basecamp came in when bike island told me i would get a refund and they were out of stock.



Based on the boxes we can see that the basecamp gravity probably has a 1 inch longer wheelbase, which would be a plus. Less tall is also a plus.



I decided to open both boxes out of curiosity.



The motobecane seems on the taller side, which is not my preference.



The gravity seems to have an extra inch in the front wheelbase... nice!



Bottom bracket wise, the motobecane does look a tiny bit stronger. The only reason is that the bottom tube is about 2mm wider, weld quality is otherwise pretty similar.

Both bikes have inner seat tube diameters of about 28mm. The outer diameter measures 32.5mm for both. So we have equivalent tube thickness at least in this area.



The motobecane seems to have the better weld quality up top, although there's some inconsistencies. The right-hand seat stay on the gravity has a small divot right where my finger is, indicating a spot of poor weld quality, or too short a tube. But the rest around it is very good and more consistent than on the motobecane. I don't know if we should call this a tie.



The bottom tube to fork tube interface is certainly better on the motobecane although there is a funky spot in the weld near the gusset. The motobecane has better tube wrap due to the gusset and greater angle of tube join. The motobecane is stronger here. The Gravity bike also has a 2mm narrower diameter bottom tube which tapers down vertically, making it weaker.



The top tube of the gravity also ovalizes as it enters the frame, and looks slightly weaker. Otherwise, the horizontal diameter in the center is identical.



Length wise, the center of the seat tube to the center of the fork puts the gravity basecamp at 1 inch longer.



Rearward, the Motobecane is maybe 0.25 inches longer, which is good, but not good enough to counter the loss of an inch in the frontend.

Parts wise, the motobecane is the far superior bike, with the gravity having a lot of crappy steel and no-name parts, and the motobecane having low end shimano parts instead. Both bikes' forks' stanchions measured at 27mm, and the basecamp's fork seems to be fully steel, but the motobecane has a steel lower, aluminum upper.

Neither bike has rear disc mounts which is a disappointment, but not dealbreaker.
Both bikes have kickstands and the one on the motobecane is much nicer.
The motobecane has 2 more chainrings, 1 more derailleur, and 1 more shifter.

The weight of the gravity with packing material still on, but without seatpost was 37lbs.
The motobecane in the same condition was 38lbs.

Considering that the gravity has a steel fork, a steel seat tube, steel handlebars, and steel cranks, the gravity seems like it could be a lighter bike overall with some component swaps because it's so disadvantaged.



I dunno man, the choice is not getting any easier. The gravity looks 5-10% weaker, but also looks nicer and the +0.75 inch of wheelbase and being lighter is a huge plus.

 

[Papa]

Assuming you have both bikes assembled,... straddle each one, seated, then try forcing the handle bars laterally (avoid rotating the HB), to check frame rigidity at the headtube.

 

[neptronix]

Unfortunately not the case.
If i were to fully unpack the motobecane, it's possible that i couldn't do a return.

I did your test with just the gravity.
I am currently 280lbs and have very good upper body strength.
Everything is tightened down and the tires are at 40 psi.

With maximum effort, I can get the frame to move left-right 1/2 of an inch in either direction.

 

[nicobie]

I've never been a fan of bent downtubes. I can't see the advantage with a bent tube only the disadvantage. I'm probably wrong though...

 

[neptronix]

Senor Papa,

You planted a seed in my mind and curiosity got the best of me.
I fitted the handlebars, front wheel, and seat of the motobecane and performed the test.

The motobecane laterally bends with less force and bends further than the gravity.
This goes for both holding the brakes and not.
I was surprised by this!

The gravity is harder to start the bend on, and gets progressively harder to bend more.

There is a big difference in these frames!

Also, the geometry of the motobecane is as such that the rear sags downwards more. The bottom bracket axle is maybe 1/3 inch lower. ( this is bad because i'm about to subtract 1.5 inches )

The headtube angle on the motobecane is a little more vertical, and this makes the effective wheelbase even shorter than the -0.75 inch difference.

With this final test, i'm wrapping up the motobecane in hopes of a return.

I feel like the gravity is the winner of this contest!

 

[Papa]

The infamous bicycle speed wobble

20 years ago, Jobst Brandt reasoned that.... "Shimmy requires a spring and a mass about which to oscillate and these are furnished by the frame and seated rider."

"Bicycle shimmy is the lateral oscillation of the head tube about the road contact point of the front wheel and depends largely on frame geometry and the elasticity of the top and down tubes."

 

[neptronix]

Update on the situation at hand..
Called bikesdirect and asked for a return on the HT300, they said yes if i paid return shipping ( $50 ).
Pretty happy about that!

I finally test rode the bike yesterday.
I need the handlebars up by 3 inches and forward 3 inches ( very typical ), and the seat is a prostate smasher.
So uncomfortable, i couldn't really get into it

Brakes seemed to work allright, fork is mostly trash due to a huge amount of stiction ( HT300's was way better ). Rear derailleur was properly tuned and the rear wheel was in true but the front a little off.

With very moderate pedaling ( as one would do with a motor ), i could not notice any flex in the frame.

Will give final impressions in the next post.

 

[Chalo]

It's fine. There's just not very much to go wrong when there aren't cheesy suspension parts or gimmicky features to crap out immediately. The cheap derayrays will wear out young if you use them much; likewise the pogo fork might not make it a full year, but won't fall apart as soon as it gets sloppy. The brake pads will most likely need replacement soon when they wear promptly.

Your favored kind of tires will protect the wheels from most of the world's cruelty.

Bikesdirect bikes tend to be about like entry-est-level bike shop bikes, just without the professional prep work.

 

[glennb]

I've never been a fan of bent downtubes. I can't see the advantage with a bent tube only the disadvantage. I'm probably wrong though...

I don’t see any advantage either.

My theory is that someone’s paid to draw the frame, and it’s easier to justify their salary by adding flourishes. Architects do this.

 

[glennb]

A drop of thin oil on the fork seals might be in order.

I’m struggling to picture this head tube flex test, or how the Gravity could win it. Stiffness ought to be a function of tube diameter, and little else. Are you sure the motobecane headset is up to scratch?

 

[neptronix]

Thanks for chiming in, Chalo.

The frame doesn't seem especially inspiring in terms of strength, it's nice but the amount of weld looks like 66% of what it was on the Turner and Trek bikes.

Tube thickness looks pretty good though. I think this is where a lot of the bike's weight stems from.
I think 30mph should be the limit on this bad boy.

I also think giant triangle on the downtube is out due to the lower strength.
Using a triple bob to get a 14s5p battery ( 17ah ) mounted extremely forward is the way i wanna go.
Would also look massively cleaner than whatever hardware store grade mounting device i put together.

 

[2old]

If you like the fork on the "other" bike, you might swap it and keep the bike for parts. You could sell the fork and "extra" frame.

 

[neptronix]

If you like the fork on the "other" bike, you might swap it and keep the bike for parts. You could sell the fork and "extra" frame.

I'm returning the motobecane, so can't do that. Also, the motobecane fork may have less stiction, but 26-27mm stanchions is so weak and flexy that it's dangerous. It's not an upgrade. The bike needs 30mm or wider to support a big fat disc brake, and also the beating that high speeds will dole out.