My DIY builds: GMAC, BBSHD, 9C RH212, CYC Photon, ToSeven DM01

Surly Troll-GMAC update:
Well it was going to happen eventually. I was in a rush to get in a quick last minute ride and thought my battery was fully charged. At about 10 miles out, the CA3 stopped with motor assist due to Low Voltage (didnt hit the battery LVC). So I turned off all power and rode it like a 50-60 lb bike with a draggy geared motor with no clutch back home. Frankly it wasnt as hard as I would have thought although I was the slowest guy on the path/trail. I did manage to keep it above 9mph despite some rolling hills and a headwind. Overall averaged 12mph for the 20 mile ride which is about the same as I do on a non-ebike (for the whole ride). I am pretty tired from the ride
But I'll bet you recorded some really great w/hr numbers ... ;)
 
Surly BC-BBSHD
Got a flat today in rear tire about 10 miles from home due to a goathead on my BC-BBSHD with 27.5x2.6 smart sams and stans in the tubes. Pulled over and added a 2oz bottle of stans and filled using a CO2 cartridge. The goathead was basically on the edge of the sidewall so the stans worked but had a slow leak and the rear tire was REALLY low on air and was all over the place in the corners.

Throttle to the rescue! It was risky putting all my weight on the seat/back tire and risking a pinch flat or traction loss so I stood up and just concentrating on putting most of my weight on the front wheel and just using the throttle. As the rear tire lost more air, it would start letting me know by sounds and squirms that I had too much weight on it. About 2 miles from home, had to fill up with another c02 cartridge.

Third flat in over 10 years or so since going to stans in tubes. The rear smart sam tire was basically bald.

Just bought a set of tannus armor inserts and will see how I like them. Will try both front and rear first and then possibly just on the rear.
 
Last edited:
😄 ... another example of the multitude of benefits of having a throttle.

It will be interesting to hear how you like the inserts. I'm not sure what to think as I've heard so many very pro and very con experiences.
 
Surly BC-BBSHD
Got a flat today in rear tire about 10 miles from home due to a goathead on my BC-BBSHD with 27.5x2.6 smart sams and stans in the tubes. Pulled over and added a 2oz bottle of stans and filled using a CO2 cartridge. The goathead was basically on the edge of the sidewall so the stans worked but had a slow leak and the rear tire was REALLY low on air and was all over the place in the corners.

Throttle to the rescue! It was risky putting all my weight on the seat/back tire and risking a pinch flat or traction loss so I stood up and just concentrating on putting most of my weight on the front wheel and just using the throttle. As the rear tire lost more air, it would start letting me know by sounds and squirms that I had too much weight on it. About 2 miles from home, had to fill up with another c02 cartridge.

Third flat in over 10 years or so since going to stans in tubes. The rear smart same tire was basically bald.

Just bought a set of tannus armor inserts and will see how I like them. Will try both front and rear first and then possibly just on the rear.
A bike shop that I bought a Scott EMTB from uses only Stans. But they said it needs to be refreshed every so often. I believe I will try FlatOut for this reason when I start installing my own sealant.
 
Just another opinion, but IMHO, it would seem what kind of sealant you run is not near as important as the fact you need to have SOMETHING in there!
 
A bike shop that I bought a Scott EMTB from uses only Stans. But they said it needs to be refreshed every so often. I believe I will try FlatOut for this reason when I start installing my own sealant.
Most certainly you have to refresh stans. My typical schedule is a new tube with fresh stans every year followed by additional stans added after 6 months. That being said, tubes dont last forever and in my experience will wear out/crack around the valve stem hole which cannot be repaired.

I know stans works for me as there is always goatheads in my tires. When I replace the tubes, the tube is pretty much stuck to the tire everywhere with dried sealant.

Ironically this tire was in need of a stans refresh at the beginning of April so my first course of action (which has always worked before) was to add a fresh bottle on the trail. Maybe it was an issue with the old stans (I have had stans form a huge solid ball which had a noticable bulge in the tire). I think its more likely that I just encountered the thorn while cornering as it was on the edge of the sidewall where the stans would not likely seal it that well.
 
Last edited:
Received the Tannus Armor and installed a set.

Installed the first insert with included tube as soon as they arrived. It was cold from being outside and all scrunched up to fit in a small box. Took lots of fiddling since the insert was cold/stiff but got it to work. This insert was installed on the back wheel which is the one that had the flat yesterday.

For the second insert, I left it outside the tire first and just inserted the tube and pumped it up to force some shape into the insert and let it all warm up in the sun. Install was super easy.

So basically the install was easy peasy. I used the 27.5x1.95-2.5 insert into my Smart Sam 27.5x2.6 tires.

Determined psi by pushing down on the tire and adjusting the feel to feel the same as a tire without the insert. Reducing the psi 5-7 psi seems about right and matches most of what I have read on google searches.

Very noticable (when not on the bike) was how much more damped the tire was when pushing on the tire or dropping it (it bounces less). Cant wait to see what the ride is like.

When I removed the old front tube (with 6 month old stans), it was firmly glued to the tire. After seperating the two, the tube immediately deflated leaving a mess of stans on the floor. I found 7 goatheads in the tire.
 
I have Tannus in several bikes. And have attempted it and failed in others. fat tires, 29ers, 26'ers... even a 20". Installation of the inserts ranges from easy to nightmarish. It all depends on the individual tire, rim and tube combo. My last two install attempts over the last week have both failed, with the most recent one being last night. Seems like the successful installs have the insert being very close to the original tire's exterior diameter (they won't stretch). Last week I tried the 2.5" versions inside of a 30mm 26" rim (Sun Ringle MTX39 w/30" internal width) housing 2.8" tires with Tuffy inserts (yes I know. Overkill.) Would not work. The 2.8" tire and the 2.5" tannus had too much difference in outside diameter and the inserts would not stretch to the tire's larger diameter. Fail.

I took those same 1.9"-2.5" inserts and tried installing last night. DT Swiss FR560 rims (32mm internal width I think) and Schwalbe 26x2.35" Pickups. This time, the Tannus fit in beautifully within the rim, and there was no diameter issue, but there was simply not enough room to get the tire bead inside the rim with the inserts inside. It was the tubeless nature of the rims this time... tubeless = tight fit on the bead and it was just not possible to fit even after I cut the insert sides down to the smaller size. I'm using a small Schwalbe Air Plus tube that fit great under the inserts without bunching.

They are definitely a mixed bag. The best description for what they do to tire performance (@linklemming noted the dampening) is they 'deaden' the tire. Its a hard lump like a dead blow hammer head. Not a good thing but for a utility bike you have to depend on day after day I think its worth that penalty. Also, since they absolutely do flatten and thin out (Tannus recommends you deflate the tire in between rides to stave this off) its a good idea to try and use a tube larger than what they recommend as sooner or later the tube will need to fill its normal sized void when the Tannus becomes paper thin.

After this latest failure I think I am done buying them.
 
Did a test ride today with the tannus inserts. Initially set pressure to 13psi F/R on my 27.5x2.6 setup which was way too low in the back(scary cornering, especially on asphalt) but felt pretty good on the front. Came back home and set pressures to 20psi F/R and did a 20mile ride.

Overall, I am very impressed. The tires definately have a different feel/sound and the dampening effect(along with lower pressures) smooths out the ride. Tire sidewall squirms more(in the rear) than I am used to but I definately notice more grip. Might take a few rides to get used to the feeling.

I think a good compromise will be 15/20psi F/R. I typically ran 25F/R(average) without the inserts. Im around 240#

Deflating after every ride is insane, no way I am going to do that. With Stans in my tubes, I was pretty lazy and would usually go up to a month before refilling (fill to 30psi and ride till they felt off). I will likely run stans with this setup as well (extra flat margin plus less fillups since the sealant keeps the tubes from slow leaks on their own).

We will see how they turn out long term.

My old setup (tubes with stans) has worked for over 15 years with only 3 flats in that time frame. I will go back to that setup if the tannus has issues. While is not obvious I was more curious about handling/traction benefits with the tannus.

Maybe I wasnt on my game today but the bike felt slower at my default BBSHD PAS setting. The tire/wheel combo at least in the front actually weighs less than my GMAC bike (heavier Johnny watts tires, 36 hole rim and beefier rims and spokes) so its not a weight thing. Im wondering if this is the dampening. There was an article I read somewhere comparing different tires sizes off road(mild) with the outcome being that the bigger tires were actually faster. I thought some of the reasoning was that the increased spring rate with a narrow tire/high pressure meant that the rebound from a bump happened faster and was more vertical whereas with a larger tire/low pressure, the rebound actually happened a little later and since the tire had rolled a bit more, the rebound was actually adding energy in the direction of travel. Dampening would ruin this.
 
Last edited:
Maybe I wasnt on my game today but the bike felt slower at my default BBSHD PAS setting. The tire/wheel combo at least in the front actually weighs less than my GMAC bike (heavier Johnny watts tires, 36 hole rim and beefier rims and spokes) so its not a weight thing. Im wondering if this is the dampening. There was an article I read somewhere comparing different tires sizes off road(mild) with the outcome being that the bigger tires were actually faster. I thought some of the reasoning was that the increased spring rate with a narrow tire/high pressure meant that the rebound from a bump happened faster and was more vertical whereas with a larger tire/low pressure, the rebound actually happened a little later and since the tire had rolled a bit more, the rebound was actually adding energy in the direction of travel. Dampening would ruin this.
Maybe try bumping up the rear psi a little more?
 
Maybe try bumping up the rear psi a little more?
I have never noticed any significant increase in effort required due to low psi, the bikes just starts handling bad.

Im thinking I just wasnt that into riding today. It also seemed like I was fighting a headwind no matter where I went :)
 
... It also seemed like I was fighting a headwind no matter where I went :)
I seem to remember that happening a lot in March/April on the front range. I thought mother nature had it in for me ... but it might have just been my level of fitness after sitting on my butt most of Jan/Feb. (life before running studded winter tires on the road) 😁
 
loading up the wheels with those inserts is not doing your efficiency any favors. I would bet its a combination of Tannus and air pressure. I've noticed the same thing but hey I have a motor so no worries. Also I consider flatproofing to be much more important on a daily driver.

FlatOut is the king of the low pressure sealants. Never dries out so lasts the life of the tire. Works as well as a tubeless sealant as it does a tube sealant. My Big Fat Dummy is running Snowshoe XLs on 90mm rims tubeless with FlatOut. Air lasts for months inside. Tubeless, it survived a 6-nail puncture (6 nails in a line from a fragment of a strip of discarded nailgun roofing nails). Tubed, it has survived a jagged 1/4" metal strip on the same bike (prior to going tubeless). Also numerous little punctures where i heard the hissing but also heard it stop. Usually unable to find the puncture if I've ridden enough to dry out the tire surface.

I've done Stans and Orange Seal over the years, as well as Slime. FlatOut by comparison is a modern take on an otherwise dated product that hasn't improved much in decades. Note I said 'low pressure' though. I have had it work on tires up to 50 psi but others have reported issues in the 60-65 (?) range. I'll know soon as I'm putting it into my current build after the Tannus failed, and that bike has 60 psi tires.
 
Great info on why to use FlatOut for anyone who wants to know. Thanks for restating it for us new to biking.

For high pressure tires I wonder if that newly released sealant with carbon fiber will be the ticket.
 
loading up the wheels with those inserts is not doing your efficiency any favors. I would bet its a combination of Tannus and air pressure. I've noticed the same thing but hey I have a motor so no worries. Also I consider flatproofing to be much more important on a daily driver.

FlatOut is the king of the low pressure sealants. Never dries out so lasts the life of the tire. Works as well as a tubeless sealant as it does a tube sealant. My Big Fat Dummy is running Snowshoe XLs on 90mm rims tubeless with FlatOut. Air lasts for months inside. Tubeless, it survived a 6-nail puncture (6 nails in a line from a fragment of a strip of discarded nailgun roofing nails). Tubed, it has survived a jagged 1/4" metal strip on the same bike (prior to going tubeless). Also numerous little punctures where i heard the hissing but also heard it stop. Usually unable to find the puncture if I've ridden enough to dry out the tire surface.

I've done Stans and Orange Seal over the years, as well as Slime. FlatOut by comparison is a modern take on an otherwise dated product that hasn't improved much in decades. Note I said 'low pressure' though. I have had it work on tires up to 50 psi but others have reported issues in the 60-65 (?) range. I'll know soon as I'm putting it into my current build after the Tannus failed, and that bike has 60 psi tires.
As far as the inserts ruining efficiency due to their added mass. The tannus front wheel/tire is actually lighter by 50g than on my GMAC bike (which has 36h instead of 32h, same hub, beefier spokes and heavier tires and tube). Maybe it has a higher polar moment of inertia due to more weight at the extremes. Maybe its just my imagination as the BBSHD does have a more dead feeling due to its PAS compared to my torque based GMAC. I will update as I ride it more. Might even just run it in the rear as a compromise

Thanks on the recommendation on the flatout, I will likely try that. Any recommendation on how much to use in a 27.5x1.75-1.95 tube? I use 30psi or lower

Im only concerned about goatheads, Im willing to excuse any hassles like refilling/refreshing to get the best performance on goatheads
 
Last edited:
Tannus Insert Final Conclusion
I think I am going to abandon the tannus inserts. Thats what I get for trying to solve a problem that didnt exist. I will just go with my old standby of tubes and sealant (stans until I run out then flatout). Oh well, no regrets.

Some of the tannus quirks (for me):

The foam is just to squishy for me no matter what tire pressure I use. While I definately notice the improved traction offroad and the inserts are pretty much perfect there, my rides are a compromise of different trail conditions including asphalt/concrete. Cornering on paved surfaces has to be tamed down quite a bit and I dont push it that hard in this scenario anywho. This will likely change as the foam compresses so its an ever changing thing to deal with.

Temperature dependent squishiness. Today was much warmer than usual and the first decent turn on a paved surface had me panic enough when I leaned over that I had to correct my steering input as I thought my front end was washing out.

These tires just feel slow and its not because weight or pressures. As I have mentioned before I think its the dampening (although I have nothing to back it up other than than at 14:45 in the following video

Who knows if this is 100% correct but I cant explain the feeling any other way.

Comparing my rides, for the same ride and the same wh/m pulled from the battery, a 1.5hr/25mile/1500ft vertical ride is about 1mph faster with the GMAC bike than the BBSHD with the tannus inserts. While there is ALOT of potential variablility in this, my rides have been pretty consistent between the BBSHD and GMAC with the only variability being wh/m vs average speed.

KInekt Seatpost Opinion
I decided to try a Kinekt Suspension Seatpost on the BC-BBSHD bike and I am 100% glad I tried. Potentially trying to solve another problem that didnt exist. I tried a suspension seatpost on a friends bike about 15 years ago and thought it was just a silly thing to do. I have owned/ridden FS MTBs since 2005 and must say I am very impressed with the Kinekt seatpost.

Just ordered a Redshift suspension seatpost to try on the GMAC bike
 
Last edited:
Looking at various options to convert a 29er hardtail mtb to an ebike. Donor bike yet to be sourced. I live in a fairly flat area except for a nearby national park that rises to 1000m elevation via a very picturesque 32km sealed road. So I need something that can climb. My research so far has me tossing up between the GMAC and BBS02. A search of GMAC vs BBS02 brought me to this thread on EBR.
Read it all, great info by Linklemming and others.

The GMAC kit plug and play including wheel build shipped to my location (Asia) would be around USD2700 (around $500 is shipping due to bulkiness of wheel). That includes Phaserunner, CA, Torque sensor, Battery.
I see the main advantages of the GMAC being regen, and option of torque sensor.

The BBS02 kit with battery incl shipping is around USD1100. Advantages are gearing options and cost. Also like the option of the Eggrider, and bluetooth connectivity with a smartphone for programming.

Aesthetics are very subjective. To my eye, the GMAC motor sitting between the gears and disc rotor is a better look then the BBS02 hanging off the BB.
However the BBS02 with Eggrider is a lot less clutter on the handlebars than the huge CA.

Anyway, thats my observations so far. Looking like cost might be the deciding factor for me.
Also note a lot of sellers are out of stock of ebike batteries containing name brand cells like Panasonic, Samsung, LG etc. Could be a show stopper for a while.
 
Looking at various options to convert a 29er hardtail mtb to an ebike. Donor bike yet to be sourced. I live in a fairly flat area except for a nearby national park that rises to 1000m elevation via a very picturesque 32km sealed road. So I need something that can climb. My research so far has me tossing up between the GMAC and BBS02. A search of GMAC vs BBS02 brought me to this thread on EBR.
Read it all, great info by Linklemming and others.

The GMAC kit plug and play including wheel build shipped to my location (Asia) would be around USD2700 (around $500 is shipping due to bulkiness of wheel). That includes Phaserunner, CA, Torque sensor, Battery.
I see the main advantages of the GMAC being regen, and option of torque sensor.

The BBS02 kit with battery incl shipping is around USD1100. Advantages are gearing options and cost. Also like the option of the Eggrider, and bluetooth connectivity with a smartphone for programming.

Aesthetics are very subjective. To my eye, the GMAC motor sitting between the gears and disc rotor is a better look then the BBS02 hanging off the BB.
However the BBS02 with Eggrider is a lot less clutter on the handlebars than the huge CA.

Anyway, thats my observations so far. Looking like cost might be the deciding factor for me.
Also note a lot of sellers are out of stock of ebike batteries containing name brand cells like Panasonic, Samsung, LG etc. Could be a show stopper for a while.
I agree with much of your assessment. I would just suggest you consider the BBSHD over the BBS02. It's not that much more money, offers all the same features, but it's a little more stout. Not just in climbing power, but also regarding the controller's ability to handle heat/abuse.

I have a MAC 12t bike conversion (about the same motor as the GMAC), and a Bafang Ultra powered bike (about the same power as the BBSHD). I can share that both are torque monsters, but the eventual climbing ability of the MAC may depend on the load. Lightly loaded with just an average sized rider, it should be a great climber. Ultimately though, ability to get the job done may depend on the difference in torque available with the mid drive motor through it ability to gear down....
 
I agree with much of your assessment. I would just suggest you consider the BBSHD over the BBS02. It's not that much more money, offers all the same features, but it's a little more stout. Not just in climbing power, but also regarding the controller's ability to handle heat/abuse.

I have a MAC 12t bike conversion (about the same motor as the GMAC), and a Bafang Ultra powered bike (about the same power as the BBSHD). I can share that both are torque monsters, but the eventual climbing ability of the MAC may depend on the load. Lightly loaded with just an average sized rider, it should be a great climber. Ultimately though, ability to get the job done may depend on the difference in torque available with the mid drive motor through it ability to gear down....
Thanks for that info. I hear that a lot about choosing the BBSHD over the BBS02B and I wont rule it out.
I weigh 70kg/154lbs, so not too heavy.
My rationale for considering the BBS02b was its supposed to have less problems with the controller than the BBS02 ?

Sounds like the MAC would also do the job for me. Hard to get hold of at the moment, and even large diameter 36 hole rims are hard to get, at least in my region. I while back I asked EM3ev to quote for a MAC motor, but they dont ship to my location.
Where did you source yours from ?
 
Last edited:
Back