TurboTight Kaabo Mantis Hinge Service Kit (M8x29 pair screw)

Renew your stem folding mechanism with TurboTight Kaabo Mantis Hinge Service Kit. The kit makes a significant improvement in reducing stem backlash (wobble) as the factory pair screw that acts as the hinge pivot bolt will typically disform over time resulting in forward/back "play" in the hinge and associated metal-on-metal creaking sounds. The TurboTight kit is a superior aftermarket approach to renewing all the relevant components to extend heavy maintenance service interval and frequency of periodic adjustment of the rider.

The Kit comprises a strong hardened steel, solid dowel pin to replace the "hollow" factory stock M8x29 pair screw.. An assortment of replacement / uplifted SF-1 bearings are included to refresh those in the stem which sit each side of the Folding Hinge along with an 8x10x15mm SF-1 bearing for the Folding Hinge itself, which resides in the center of the pin.

Typically the Folding Hinge, Stem, Locking Cup (clamp), Quick Locks and Hinge Fix Ring (Collar) need not be replaced as part of renewal works.

The kit renews with the following items:

• (1) A strong, hardened alloy steel solid dowel pin: This replaces the factory stock pair screw which will typically bend from intermediate wear. The solid pin supports higher load ratings without deformation.
• (2) Self-lubricating bearings & bushings for the stem: The it includes three sets, fit as appropriate as relevant to the extent of wear around the cast holes in the alloy stem, and condition of the factory stock bearing:
  • Two pairs of 8x10's:
    • (2a) 8x10x6 SF-1 bearings, identical to stock. Provided as a point-of-reference to compare with the original deformed ones, for use with the factory stock pair screw.
    • (2b) 8x10x10 bushings, which has a longer 10mm length to assist placement/positioning. More resilient than SF-1. Best fitted when wear is intermediate.
  • A pair of 8x12x10 bushings:
    • (2c) Fit these if the stem's cast holes holes are more significantly deformed. You will need bore out the 10mm hole in the stem to a nice fresh round 12mm. See notes.
• (3) Countersunk adjustment screw and a series of washers: The (8mm) length of the factory stock screw is typically shorter than desired, so renew with the included, 2mm longer (10mm) and an appropriate "backfill" washer from the selection included in the kit. The screw is responsible for setting the limit as to how "vertical" the stem can extend and also influences the pressure applied on the Locking Cup (clamp). Once you have fitted the appropriate mix of washers and bedded in, apply medium strength blue thread locker. You should not then need to mess with it too much, set and forget!.
• (4) Self-lubricating bearing for the Folding Hinge: An 8x10x15mm self-lubricating bearing is provided to renew that in the Folding Hinge so that it closely matches the diameter of the pin.

Instructional video:

Detailed list of contents:

1) An M8 (8mm) x 35mm Hardened Alloy Steel Dowel Pin, featuring:

• Replaces the factory stock pair screw.
• Pin Diameter 8.003 ~ 8.009mm. Point Diameter: 7.4~7.8mm. Manufacturer to DIN 6325. Rockwell Hardness: RC 60 Surface, RC 50-58 Core. Finish: Plain - Not Coated.

2a) A pair of 8x10x6 self-lubricating bearings:

• Identical to factory stock bearing, for use with factory stock pair screw.
• Self Lubricating composite design comprising steel backing + bronze powder + PTFE bearing design, designation SF-1 0806.
• Dry bearing (need not lubricate). Low carbon steel (100n/mm2 load capacity). Low wear, low friction, allows slippage, reduced noise / creak. Friction Coefficient: 0.03~0.02. PV Limit (dry): 3.2N/mm2. m/s. PV Limit (oil): 25N/mm2. m/s.

2b) A pair of 8x10x10 bushings:

• Best fitted when wear is intermediate.

2c) A pair of 8x12x12 bushings:

• Fitted when wear is significant, ref notes to bore casting from 10mm to 12mm.

3a) An M5 10mm countersunk (conical) socket screw:

• 2mm longer than the 8mm factory stock stock screw.
• Alloy Steel heat treated. Tensile Strength typically 12.9 class (or 10.9) Thread pitch 0.08p course (0.80mm). 3mm allen key socket size (hex). 3.10mm head height.

3b) Four washers, stainless steel, M5 x 10mm use as required to backfill countersunk screw:

• 1 x 0.5mm belleville (conical) washer (fit this one first to trial thickness).
• 3 x flat washers:
  • 1 x M5 x 10mm x 0.3mm ultra thin (fitted where wear is minimal or as 0.3+0.5=0.8mm where wear is moderate).
  • 1 x M5 x 10mm x 0.5mm thin.
  • 1 x M5 x 10mm x 1.0mm thick (extensive wear, rarely used, consider plating the stem).

4) An 8x10x15mm self-lubricating bearing:

• To renew that in the Folding Hinge.

Notes:

1. Product launched 2021, over 100+ units sold with a couple of continuous improvement revisions which accommodate more severely damaged stems. Some product images will show prior versions.
2. Supports Mantis 8 and 10 series scooters (including Lite, Duo, Pro & SE) with double or triple Locking Cup (clamp) (all Mantis other than the King GT).
3. Where deformation in the stem casting is more significant, 8x12x10 bushings should be fitted with process of boring out the 10mm hole in the stem to 12mm diameter. This refactors the casting. This restores out-of-round shaped hole in stem to be true round without any "play". Product images show drilling out the casting in the stem and which are also published in this post in eScootNow - The Facebook Group (02/10/2024).
   
   
4. As there is no pair screw with the implementation, the bushes, particularly the smaller factory original 8x10x6 self-lubricating bearing can dislodge relatively easy when unfolded. Keep an eye on it when folding and lying scooter down on side. If a firmer fit is required, progress to the more substantial bushings and/or apply a two-part metal epoxy to secure them - you can also apply to the end of the dowel pin.
5. Thoroughly clean your hinge cavities including countersunk socket thread with a good flush of something such as PTFE before installation. Do not use oil based lubricants such as standard WD-40 or lithium grease as these will attract foreign materials (e.g. dust and dirt) that will cause premature failure of hardware and introduce squeaking sounds.
6. Image showing 8x10x10 bushing fitted to the stem.
   
   
7. The Bakelite knob fitted to the center creates more clearance to assists fingers reach the adjacent quick lock knobs.
   
8. There is also a service interval on the M10 vertical stem bolt (the one above the tyre). If renewing, eSN recommends an M10x80mm high tensile 12.9 or 10.9 class with Nord-Lock style wedge washer which works out slightly longer than stock, further details mentioned on folding hinge product page.